Is there a shorthand for recalculating CR if I just halved it's hit points?

[Mr Adventurer]

I wanted the full experience of fighting the monster, but decided that it would retreat when at half hit points, so I'd like to adjust the CR downward to reflect the reduced threat (hp and resources saved from the second half of the battle). I know I can use the DMG chart to work out the offensive and defensive CR using the amended hp total, but is there a shorthand calculation that I can apply for this straightforward change, to save myself some effort?

[Unoriginal]

I wanted the full experience of fighting the monster, but decided that it would retreat when at half hit points, so I'd like to adjust the CR downward to reflect the reduced threat (hp and resources saved from the second half of the battle). I know I can use the DMG chart to work out the offensive and defensive CR using the amended hp total, but is there a shorthand calculation that I can apply for this straightforward change, to save myself some effort?

"Fleeing when reaching half HPs" is a tactical consideration, and tactical consideration do not change the CR.

A Fire Giant has the same CR whether you encounter one ambushing the party through a magic portal or one sleeping on the job.

[Mr Adventurer]

There's no difference from a mechanical perspective whether I decided they would flee or whether I decided to reduce their hit points by 50%.

[Unoriginal]

There's no difference from a mechanical perspective whether I decided they would flee or whether I decided to reduce their hit points by 50%.

Fleeing is not dying. Unless you just make them pop out of existence/make a cutscene happen with no chance of pursuing them?

[MoiMagnus]

"Fleeing when reaching half HPs" is a tactical consideration, and tactical consideration do not change the CR.

A Fire Giant has the same CR whether you encounter one ambushing the party through a magic portal or one sleeping on the job.

"Fleeing at half HP" still has an influence per RAW. If you want to compute the difficulty of the encounter with the DMG tables, you are supposed to take in account circumstances as modifiers. They don't change the CR of the creatures and the XP won in case of victory, but they change the rating of the encounter.

And for that, the rules are pretty simple (as you said, no CR adjustment). Just reduce the rating by one rank (medium -> easy or difficult -> medium) if the enemies have a significant handicap compared to the normal assumption. And I think that if the default assumption is that the enemies fight to the death, them not doing so is an handicap.

[The_Jette]

There's no difference from a mechanical perspective whether I decided they would flee or whether I decided to reduce their hit points by 50%.

There really is, though. Suppose your enemy has 120 hp. Well, turning and running at 60 hp is not the same as a 60 hp creature dying. For one thing, the players could do more than 60 hp of damage. It might not get to flee (due to turn order) until it reaches 20 hp. At that point, the 60 hp creature would have been dead for some time. Plus, depending on how many hp the enemy starts with (since you haven't given a starting point to work with), the enemy could get close to 50% hp and then the players have a lucky round and drop it before it gets a chance to flee. Or, are you going to set up some kind of contingency spell that has the enemy teleport away at exactly 50% health?

[DragonBaneDM]

You might already be aware of tools like this one:
https://5e.tools/crcalculator.html#0,13,1,3,false,Medium,1,10,false ,0,false,0,

But just in case it takes a while for folks who know what fraction of total CR hit points account for, you can use this instead!

Honestly, the more I think about it, the more I think that there’s not gonna be an easy “oh it’s just an eighth of the total CR!” The higher a monster’s CR goes, the more of an impact a full 1/2 cut in HP will have, but the more likely it gets that the monster has things like Magic Resistance or nonmagical damage resistances.

I honestly think you’re safer calculating it for each individual instance.

[Mr Adventurer]

Fleeing is not dying.

Mechanically in this specific circumstance there is no difference, I say again.


Unless you just make them pop out of existence/make a cutscene happen with no chance of pursuing them?

Neither of these things you have invented are necessary.


There really is, though.

Not necessarily.


Suppose your enemy has 120 hp. Well, turning and running at 60 hp is not the same as a 60 hp creature dying. For one thing, the players could do more than 60 hp of damage. It might not get to flee (due to turn order) until it reaches 20 hp. At that point, the 60 hp creature would have been dead for some time. Plus, depending on how many hp the enemy starts with (since you haven't given a starting point to work with), the enemy could get close to 50% hp and then the players have a lucky round and drop it before it gets a chance to flee.

None of that is applicable in this case, which is why I made the thread.


Or, are you going to set up some kind of contingency spell that has the enemy teleport away at exactly 50% health?

In one case, yes, a spellcasting enemy had a contingency spell.


You might already be aware of tools like this one:
https://5e.tools/crcalculator.html#0,13,1,3,false,Medium,1,10,false ,0,false,0,

But just in case it takes a while for folks who know what fraction of total CR hit points account for, you can use this instead!

Honestly, the more I think about it, the more I think that there’s not gonna be an easy “oh it’s just an eighth of the total CR!” The higher a monster’s CR goes, the more of an impact a full 1/2 cut in HP will have, but the more likely it gets that the monster has things like Magic Resistance or nonmagical damage resistances.

I honestly think you’re safer calculating it for each individual instance.

This is really helpful, thank you very much. I appreciate the info that there's not likely to be a shortcut. I'll revert to using the charts and any calculator.

[Darzil]

Mechanically in this specific circumstance there is no difference, I say again.
I guess it teleports out or something then, but the players somehow know it is not going to return, or tell anyone about their presence, or bring reinforcements?

Because a monster running away will often be a thing you are willing to put yourself in danger to prevent if there is any chance that them getting away might cause further trouble.

[Unoriginal]

The use of Contingency to trigger an escape at exactly 50% HPs is a tactical concern which does not affect the creature's CR.

There is no guarantee the Contingency persists during the fight, and there is many ways the caster could be defeated without reaching 50% HPs.

[The_Jette]

None of that is applicable in this case, which is why I made the thread.

Please explain why none of it is applicable, since all you said was that you'll be having a non-disclosed enemy flee in a non-disclosed manner once they reach half health. As Unoriginal has been saying, fleeing combat is a tactical decision, which doesn't change the enemy's CR.

[MaxWilson]

I wanted the full experience of fighting the monster, but decided that it would retreat when at half hit points, so I'd like to adjust the CR downward to reflect the reduced threat (hp and resources saved from the second half of the battle). I know I can use the DMG chart to work out the offensive and defensive CR using the amended hp total, but is there a shorthand calculation that I can apply for this straightforward change, to save myself some effort?

The DMG chart is surprisingly linear in stretches, although the coefficient varies (e.g. monsters gain about 15 HP per CR between CR 1 and CR 19, and 45 HP per CR between 20 and 30) and of course they gain other stats too. Moreover the first 80ish HP a monster gets go towards making it CR 1, which also messes up the math because cutting a monster's HP in half probably means you wind up not much over that first 80 HP.

In terms of actual difficulty the rule of thumb is clear: difficulty scales linearly in both HP and DPR, so cutting a monster's HP in half makes it (sort of) half as difficult. But the CR chart isn't actually measuring difficulty, so... my advice is to just cut the XP you award by about 25%, but otherwise don't bother to recalculate the CR. (Cutting it by only 25% instead of 50% is deliberately erring on the side of being generous to the players.)

Anyway, to answer your question: a monster with offensive CR 10 (3 attacks at +7 for 3d10+5 damage each) and defensive CR 1 (80 HP, AC 13) has a CR of 5ish; if you cut its HP in half its defensive CR goes down to CR 1/4, but the average is still approximately 5ish. On the other hand, a monster with an offensive CR of 2 (one attack at +4 for 3d6) and a defensive CR of 12 (250 HP, AC 17) loses almost 125/15 = 8.3 steps of defensive CR (it goes down to 4, then regains 1 from keeping its AC 17). Its new defensive CR is 5, so its total CR changes from 7 to 3.5ish. So I guess if you're looking for a really quick and dirty method, you could just say that every 40 HP lost is worth about 1 CR.

[Mr Adventurer]

The use of Contingency to trigger an escape at exactly 50% HPs is a tactical concern which does not affect the creature's CR.

There is no guarantee the Contingency persists during the fight, and there is many ways the caster could be defeated without reaching 50% HPs.


Please explain why none of it is applicable, since all you said was that you'll be having a non-disclosed enemy flee in a non-disclosed manner once they reach half health. As Unoriginal has been saying, fleeing combat is a tactical decision, which doesn't change the enemy's CR.

I'll not let the two of you bully me into arguing about things that are irrelevant to the thread.


The DMG chart is surprisingly linear in stretches, although the coefficient varies (e.g. monsters gain about 15 HP per CR between CR 1 and CR 19, and 45 HP per CR between 20 and 30) and of course they gain other stats too. Moreover the first 80ish HP a monster gets go towards making it CR 1, which also messes up the math because cutting a monster's HP in half probably means you wind up not much over that first 80 HP.

In terms of actual difficulty the rule of thumb is clear: difficulty scales linearly in both HP and DPR, so cutting a monster's HP in half makes it (sort of) half as difficult. But the CR chart isn't actually measuring difficulty, so... my advice is to just cut the XP you award by about 25%, but otherwise don't bother to recalculate the CR. (Cutting it by only 25% instead of 50% is deliberately erring on the side of being generous to the players.)

Anyway, to answer your question: a monster with offensive CR 10 (3 attacks at +7 for 3d10+5 damage each) and defensive CR 1 (80 HP, AC 13) has a CR of 5ish; if you cut its HP in half its defensive CR goes down to CR 1/4, but the average is still approximately 5ish. On the other hand, a monster with an offensive CR of 2 (one attack at +4 for 3d6) and a defensive CR of 12 (250 HP, AC 17) loses almost 125/15 = 8.3 steps of defensive CR (it goes down to 4, then regains 1 from keeping its AC 17). Its new defensive CR is 5, so its total CR changes from 7 to 3.5ish. So I guess if you're looking for a really quick and dirty method, you could just say that every 40 HP lost is worth about 1 CR.

Thanks Max, this is really interesting analysis, I appreciate that you've done this. The 25% hack makes an intuitive sense to me because it's lost half it's defensive CR which is half it's overall CR.

[birdboye713]

I'll not let the two of you bully me into arguing about things that are irrelevant to the thread.

Obviously, I'm not either of them, but I recommend against instantly dismissing any ideas that are still relevant to the topic. I'd argue that they're right and that there isn't really a need to adjust it. I had an encounter once where the party (made up of five level 5 characters) was fighting some tough enemies that I was going to have flee to slightly pull back the difficulty. The party ended up blocking off their escape and fought them to the end. Don't plan that there will be a 100% chance of a successful retreat, as it's possible the party could stop it.

[Unoriginal]

I'll not let the two of you bully me into arguing about things that are irrelevant to the thread.

I am not bullying you or anyone else. I apologize I did anything that you perceived as such, as it was not my intent.

If you feel I am engaging in behavior that breaks the rules, I encourage you to report the posts.

EDIT: if it's because of the post I deleted, I apologize. I misunderstood what happened as something really insulting, and I saw red. I does not excuse anything, still.



Aside from that, you asked what was the impact on CR of a monster retreating when they reach 50% HPs, and the answer is "none", so I don't see how it is irrelevant.

[iTreeby]

You can also use monsters that are actually at half health because they fought something else. I use this technique to show how strong a new type of monster is, without it being too much of a threat. It's good to recalculate the CR so that you don't accidentally TPK or over experience the party.

[GiantOctopodes]

I 100% disagree that tactical considerations should not impact your CR calculations. If you treat a group of 8 kobolds with crossbows and a tar trap the same, regardless of if the 8 kobolds are out in the open in a room with the tar trap behind them cutting off their escape, or if the kobolds are on the other side of walls shooting through murder holes into the only hallway providing passage to the player's destination, with one of them next to a switch to drop the floor to the tar trap below the players and another with a lit torch next to them, things are going to get really ugly really fast in both cases and provide very unsatisfying combats all around. In my experience at times halving or doubling the CR based on tactical considerations is often not enough, assuming you a) include interesting tactical considerations in the first place (highly recommended) and b) you and your players are both prone to using those tactical considerations.

It's really underdeveloped in the DMG and Monster Manual unfortunately all around, which largely assumes players and enemies are fighting in moderately sized empty rooms until one of them or the other dies. That being said, as others have pointed out, fleeing at half health is Not the same as halving their health, nor is it the same as having them start at half health, all of which modulate difficulty in varying degrees (it affects focus and damage on the target, their ability to heal over original thresholds, etc etc etc). Frankly, for most intelligent sentient enemies who have the chance to do so, fleeing at half health or if the battle is turning in an unfavorable way should be the rule, not the exception. Unless there's something wrong with you, when 3 of your friends have been blasted to bits and the attention turns on you, an already wounded individual, charging up and hoping to get in a few hits before you die rather than fleeing is aberrant behavior, unless you have cause to believe fleeing would not be reasonably possible or that it wouldn't matter for some reason (your master will kill you anyway on your return or something). Personally I tend to treat enemies that have predetermined escape routes or other attributes that make them more likely to flee than normal as having roughly 75% of their EHP as far as CR is concerned

For a quick calculation on reducing EHP, it is my experience that adjusting the CR by the same percentage you adjust their HP is typically "close enough" for characters up to level 11. A monster with twice as many HP as another will typically have roughly 4x the CR for values from 1-10, 2x the CR from 10-20, or 1.5x the CR from 20-30 (as HP become less important as level goes up and Save or Lose effects become more prominent). That being said, there is a lot more than HP weighing in, and all other stats will be unaffected. So for most enemies, just adjusting by the same amount as I'm modifying the HP prior to 11 and half that amount after 11 tends to be fine, and in my experience ends up being "close enough" to have satisfying combat encounters, which is all you're really looking for from CR anyway.

[PhoenixPhyre]

I 100% disagree that tactical considerations should not impact your CR calculations. If you treat a group of 8 kobolds with crossbows and a tar trap the same, regardless of if the 8 kobolds are out in the open in a room with the tar trap behind them cutting off their escape, or if the kobolds are on the other side of walls shooting through murder holes into the only hallway providing passage to the player's destination, with one of them next to a switch to drop the floor to the tar trap below the players and another with a lit torch next to them, things are going to get really ugly really fast in both cases and provide very unsatisfying combats all around. In my experience at times halving or doubling the CR based on tactical considerations is often not enough, assuming you a) include interesting tactical considerations in the first place (highly recommended) and b) you and your players are both prone to using those tactical considerations.

It's really underdeveloped in the DMG and Monster Manual unfortunately all around, which largely assumes players and enemies are fighting in moderately sized empty rooms until one of them or the other dies. That being said, as others have pointed out, fleeing at half health is Not the same as halving their health, nor is it the same as having them start at half health, all of which modulate difficulty in varying degrees (it affects focus and damage on the target, their ability to heal over original thresholds, etc etc etc). Frankly, for most intelligent sentient enemies who have the chance to do so, fleeing at half health or if the battle is turning in an unfavorable way should be the rule, not the exception. Unless there's something wrong with you, when 3 of your friends have been blasted to bits and the attention turns on you, an already wounded individual, charging up and hoping to get in a few hits before you die rather than fleeing is aberrant behavior, unless you have cause to believe fleeing would not be reasonably possible or that it wouldn't matter for some reason (your master will kill you anyway on your return or something). Personally I tend to treat enemies that have predetermined escape routes or other attributes that make them more likely to flee than normal as having roughly 75% of their EHP as far as CR is concerned

For a quick calculation on reducing EHP, it is my experience that adjusting the CR by the same percentage you adjust their HP is typically "close enough" for characters up to level 11. A monster with twice as many HP as another will typically have roughly 4x the CR for values from 1-10, 2x the CR from 10-20, or 1.5x the CR from 20-30 (as HP become less important as level goes up and Save or Lose effects become more prominent). That being said, there is a lot more than HP weighing in, and all other stats will be unaffected. So for most enemies, just adjusting by the same amount as I'm modifying the HP prior to 11 and half that amount after 11 tends to be fine, and in my experience ends up being "close enough" to have satisfying combat encounters, which is all you're really looking for from CR anyway.

The DMG is crystal clear that CR is not about calculating encounter difficulty as a whole, at least not directly. It's one metric that can be used by new DMs as a threshold check or quick-pass filter before moving on.

CR is the average of the approximate answers to two questions:
* What is the level of baseline characters against which this creature is likely to survive 3 rounds of direct attention? --> Defensive CR
* What is the level of the baseline characters against which this creature is almost capable of downing a character from 100% to 0 HP in one round? --> Offensive CR

This means that a "balanced" (oCR == dCR) creature of CR X will generally get to use its special tricks once against a party of level X baseline characters, and isn't a significant risk to one-turn KO any party members unless it gets really lucky. So in that sense, CR X is the highest CR that's safe to use against a party of level X baseline characters.

The DMG then goes on to talk about the rest of the matter, the part that numbers don't help with. Things that don't affect CR (which remember only cares about adjusted damage output and adjusted HP), but do affect difficulty. Those can't be boiled down to numbers, because they're too variable. You'd either need a math degree and a spreadsheet (and still get it mostly wrong a lot of times) or multiple books worth of descriptions. Or you'd have to nail things down like 4e did, where all monsters of a given level/role were basically skins over the same numbers and abilities. And even then 4e was pretty swingy depending on exact situations.

-------------

On the original question, I concur that a rough rule of thumb of "+-1 CR for every 40 HP you add/remove" is about as good as you'll get for a shorthand. Falls apart for some monsters, but for the average ones it's ok.

Baseline means no variant rules (including feats or multiclassing), "normal" optimization (ie following the quick build instructions), and no magic items. Yes that's low for most games. On purpose--it's designed as a ceiling on difficulty. Adding in variant rules, optimization, tactics, etc makes things easier/makes parties capable of fighting higher-CR foes. They're not necessary for following the encounter tables.

[Yakk]

Sure.

Assuming no resists or the like, shave off 1 CR for 32 HP. Also adjust proficiency bonus for new CR. (32 instead of 30 because of "free" AC from higher defensive CR).

[Unoriginal]

I 100% disagree that tactical considerations should not impact your CR calculations. If you treat a group of 8 kobolds with crossbows and a tar trap the same, regardless of if the 8 kobolds are out in the open in a room with the tar trap behind them cutting off their escape, or if the kobolds are on the other side of walls shooting through murder holes into the only hallway providing passage to the player's destination, with one of them next to a switch to drop the floor to the tar trap below the players and another with a lit torch next to them, things are going to get really ugly really fast in both cases and provide very unsatisfying combats all around. In my experience at times halving or doubling the CR based on tactical considerations is often not enough, assuming you a) include interesting tactical considerations in the first place (highly recommended) and b) you and your players are both prone to using those tactical considerations.

This is not a CR calculation.

Tactical considerations have a HUGE impact on the difficulty of the fight, yes. That is indisputable. But it is not a question of CR.

To put it in other words, CR is completely separated from context.

20 kobolds have the same CR no matter if they're ambushing the PCs after the PCs got two Exhaustion levels or if they're the ones getting ambushed. A Vampire's CR does not change if there is a river within 10ft of the PCs, or if the PCs are attacking the vampire's tomb during the day. A Rakshasa's CR is not modified if they're fighting 4 lvl 9 Wizards.



It's really underdeveloped in the DMG and Monster Manual unfortunately all around, which largely assumes players and enemies are fighting in moderately sized empty rooms until one of them or the other dies.

Neither the DMG nor the MM assume that. It is just not factors taken into account with the CR calculation.





Frankly, for most intelligent sentient enemies who have the chance to do so, fleeing at half health or if the battle is turning in an unfavorable way should be the rule, not the exception. Unless there's something wrong with you, when 3 of your friends have been blasted to bits and the attention turns on you, an already wounded individual, charging up and hoping to get in a few hits before you die rather than fleeing is aberrant behavior, unless you have cause to believe fleeing would not be reasonably possible or that it wouldn't matter for some reason (your master will kill you anyway on your return or something).

This is true. The main reasons why enemies would not flee are: being blinded by emotions or overconfidence, fanaticism, not being free to make decisions (for controlled or mindless enemies), being physically unable to flee, being unable to realize the battle is going wrong for your side, or as you said if they believe the consequences for fleeing would be worse than dying there (including "I'll sacrifice myself to let the others flee because I think it's better than having everyone die" and the like).



Personally I tend to treat enemies that have predetermined escape routes or other attributes that make them more likely to flee than normal as having roughly 75% of their EHP as far as CR is concerned

CR is not concerned by this, at all.



The DMG then goes on to talk about the rest of the matter, the part that numbers don't help with. Things that don't affect CR (which remember only cares about adjusted damage output and adjusted HP), but do affect difficulty. Those can't be boiled down to numbers, because they're too variable. You'd either need a math degree and a spreadsheet (and still get it mostly wrong a lot of times) or multiple books worth of descriptions.

Indeed.

[MaxWilson]

The DMG then goes on to talk about the rest of the matter, the part that numbers don't help with. Things that don't affect CR (which remember only cares about adjusted damage output and adjusted HP), but do affect difficulty. Those can't be boiled down to numbers, because they're too variable. You'd either need a math degree and a spreadsheet (and still get it mostly wrong a lot of times) or multiple books worth of descriptions. Or you'd have to nail things down like 4e did, where all monsters of a given level/role were basically skins over the same numbers and abilities. And even then 4e was pretty swingy depending on exact situations.


Oddly, the DMG then proceeds to ignore this adjusted difficulty when computing adventuring day XP budgets, which is especially unfortunate because the adventuring day budget, while still easy, tends to be less wildly off than the encounter difficulty rating. E.g. I'd have more hesitation about running PCs through Hard encounters until they hit 600% of the daily budget than about running them through a Deadly x4 and then a Deadly x6 encounter which together add up to 250% of the daily budget. And yet, circumstantial modifiers only affect encounter difficulty, not daily budget consumption.

It's probably fair to say something like "if the party is fighting under adverse circumstances such as being automatically surprised or fighting in total darkness without darkvision when the monsters do have darkvision, you may opt to double or rarely even triple how much of the daily XP budget gets consumed by that encounter. This rule of thumb is to ensure that you won't accidentally TPK the party without realizing that they're running low on resources. It is okay to exceed the budget on purpose when you want a deadly challenge."

[GiantOctopodes]

The DMG is crystal clear that CR is not about calculating encounter difficulty as a whole, at least not directly. It's one metric that can be used by new DMs as a threshold check or quick-pass filter before moving on.

CR is the average of the approximate answers to two questions:
* What is the level of baseline characters against which this creature is likely to survive 3 rounds of direct attention? --> Defensive CR
* What is the level of the baseline characters against which this creature is almost capable of downing a character from 100% to 0 HP in one round? --> Offensive CR

This means that a "balanced" (oCR == dCR) creature of CR X will generally get to use its special tricks once against a party of level X baseline characters, and isn't a significant risk to one-turn KO any party members unless it gets really lucky. So in that sense, CR X is the highest CR that's safe to use against a party of level X baseline characters.

The DMG then goes on to talk about the rest of the matter, the part that numbers don't help with. Things that don't affect CR (which remember only cares about adjusted damage output and adjusted HP), but do affect difficulty. Those can't be boiled down to numbers, because they're too variable. You'd either need a math degree and a spreadsheet (and still get it mostly wrong a lot of times) or multiple books worth of descriptions. Or you'd have to nail things down like 4e did, where all monsters of a given level/role were basically skins over the same numbers and abilities. And even then 4e was pretty swingy depending on exact situations.

-------------

On the original question, I concur that a rough rule of thumb of "+-1 CR for every 40 HP you add/remove" is about as good as you'll get for a shorthand. Falls apart for some monsters, but for the average ones it's ok.

Baseline means no variant rules (including feats or multiclassing), "normal" optimization (ie following the quick build instructions), and no magic items. Yes that's low for most games. On purpose--it's designed as a ceiling on difficulty. Adding in variant rules, optimization, tactics, etc makes things easier/makes parties capable of fighting higher-CR foes. They're not necessary for following the encounter tables.

Though I strongly disagree with your initial set of statements, nor do I find it particularly relevant to the discussion at hand. My assertion was that when attempting to rate the challenge that an encounter will provide, failing to account for tactical considerations will lead to unsatisfactory results. Do you disagree with that assertion at all? More relevantly, the rule of thumb of +- 1 CR per 40 HP, though differing from my methodology in practice and results, seems easy, practical, and testing a few examples results in things "close enough" to my own ad hoc approximations that though I don't have significant experience using that methodology myself it seems sound, especially based on multiple people vouching for it, just fwiw.


This is not a CR calculation.

Tactical considerations have a HUGE impact on the difficulty of the fight, yes. That is indisputable. But it is not a question of CR.

To put it in other words, CR is completely separated from context.

20 kobolds have the same CR no matter if they're ambushing the PCs after the PCs got two Exhaustion levels or if they're the ones getting ambushed. A Vampire's CR does not change if there is a river within 10ft of the PCs, or if the PCs are attacking the vampire's tomb during the day. A Rakshasa's CR is not modified if they're fighting 4 lvl 9 Wizards.

Neither the DMG nor the MM assume that. It is just not factors taken into account with the CR calculation.

CR is not concerned by this, at all.



Regardless of what you feel CR can or should calculate, from a practical standpoint what a CR is used for is to balance encounters. Saying "CR doesn't cover that" isn't particularly helpful unless you have something else to offer which Does achieve the goal at hand - crafting satisfying encounters. My assertion is that yes, environmental and tactical considerations should absolutely be incorporated when attempting to rate the challenge provided by an encounter. Beyond the sole guidance offered by the DMG in regards to that of increasing or decreasing encounter difficulty by one step per favorable / unfavorable circumstance (which again imho is woefully inadequate guidance but hey at least it's something?), it is my position that attempting to approximate, however loosely, the difference in challenge provided by tactical and environmental considerations will result in crafting more satisfactory encounters than ignoring those considerations entirely. Based on your assertion that it's indisputable they have a huge impact, it would be surprising if you were to disagree with that, so if you have actual advice or guidance to contribute in relation to How to account for that when rating the challenge a monster or encounter will provide, imho that would be more helpful than repeated assertions that CR ignores such things.

[PhoenixPhyre]

Though I strongly disagree with your initial set of statements, nor do I find it particularly relevant to the discussion at hand. My assertion was that when attempting to rate the challenge that an encounter will provide, failing to account for tactical considerations will lead to unsatisfactory results. Do you disagree with that assertion at all? More relevantly, the rule of thumb of +- 1 CR per 40 HP, though differing from my methodology in practice and results, seems easy, practical, and testing a few examples results in things "close enough" to my own ad hoc approximations that though I don't have significant experience using that methodology myself it seems sound, especially based on multiple people vouching for it, just fwiw.



Regardless of what you feel CR can or should calculate, from a practical standpoint what a CR is used for is to balance encounters. Saying "CR doesn't cover that" isn't particularly helpful unless you have something else to offer which Does achieve the goal at hand - crafting satisfying encounters. My assertion is that yes, environmental and tactical considerations should absolutely be incorporated when attempting to rate the challenge provided by an encounter. Beyond the sole guidance offered by the DMG in regards to that of increasing or decreasing encounter difficulty by one step per favorable / unfavorable circumstance (which again imho is woefully inadequate guidance but hey at least it's something?), it is my position that attempting to approximate, however loosely, the difference in challenge provided by tactical and environmental considerations will result in crafting more satisfactory encounters than ignoring those considerations entirely. Based on your assertion that it's indisputable they have a huge impact, it would be surprising if you were to disagree with that, so if you have actual advice or guidance to contribute in relation to How to account for that when rating the challenge a monster or encounter will provide, imho that would be more helpful than repeated assertions that CR ignores such things.

Encounters don't have CR. Only individual creatures do, and that's completely disconnected from context. Don't read too much into the name. {scrubbed]. It's quite clear what CR is and isn't. Nominative determinism is an error--names do not encode everything.

CR is a first-pass filter. That's all. That's all it's designed for. To quickly and simply help new DMs filter out monsters that may be inappropriate for their party.

Edit: and my first statements weren't assumptions. They're basically black-letter text, with the results of lots and lots of calculations. Calculations that agree with everyone else who has tackled this topic. That's what CR means at its core. Can it survive? Will it kill someone outright?

And sure, encounter difficulty depends on tactics. But not in some linear, mathematical way. You cannot include such characteristics in guidelines, other than to note that circumstances may make encounters much more or less difficult than expected. The guidelines (including the encounter-building guidelines) are set at a generous floor. Most parties can handle more. And there's even word-of-god that they're not rules or even design math--they're empirical effects after testing. "here's where our test parties started to run out of resources, including a safety margin". That's what those tables mean. Not "we designed it so you should fight XYZ and if you don't you're doing it wrong." And experienced DMs are intended to eventually start departing from and flat out ignoring those guidelines once they're comfortable with what their party can handle and what their party likes. They're a beginner's crutch, not some form of system design assumptions.

[Tanarii]

Though I strongly disagree with your initial set of statements, nor do I find it particularly relevant to the discussion at hand. My assertion was that when attempting to rate the challenge that an encounter will provide, failing to account for tactical considerations will lead to unsatisfactory results. Do you disagree with that assertion at all?
But don't adjust CR to do that. You adjust the final difficulty of the encounter. After calculating the base difficulty from creature CR, PC level, and number of enemies, then you adjust the final difficulty for tactical considerations like "enemy flees at half hit points".

Unfortunately, what this doesn't do (per the DMG) is change the XP awarded for the encounter, which is what the OP wants to do.

I don't agree with that personally, I think XP awarded should be for adjusted difficulty, not per individual creature CR then summed. OTOH 5e advancement is fast enough as is. Although this particularly example would slow it down, since we're talking about adjusting encounter difficulty down. But far more normally, you fight a adjusted XP difficulty 2+ times more than the sum of creature CR XP.

(Of course, as MaxWilson indirectly notes, tactical considerations don't actually adjust encounter difficulty XP either. They just adjust the difficult name/category, unlike the creature numbers multiplier.)

[JNAProductions]

Asking for clarity is not bullying.

And Challenge Rating is not the end-all be-all of how hard a monster is. It’s a good first pass-but as mentioned above, the actual encounter is more than just numbers.

[Tanarii]

And Challenge Rating is not the end-all be-all of how hard a monster is. It’s a good first pass-but as mentioned above, the actual encounter is more than just numbers.
OTOH expecting that XP awarded should be adjusted for final encounter difficulty (before player activity) is hardly surprising.

[PhoenixPhyre]

But don't adjust CR to do that. You adjust the final difficulty of the encounter. After calculating the base difficulty from creature CR, PC level, and number of enemies, then you adjust the final difficulty for tactical considerations like "enemy flees at half hit points".

Unfortunately, what this doesn't do (per the DMG) is change the XP awarded for the encounter, which is what the OP wants to do.

I don't agree with that personally, I think XP awarded should be for adjusted difficulty, not per individual creature CR then summed. OTOH 5e advancement is fast enough as is. Although this particularly example would slow it down, since we're talking about adjusting encounter difficulty down. But far more normally, you fight a adjusted XP difficulty 2+ times more than the sum of creature CR XP.

(Of course, as MaxWilson indirectly notes, tactical considerations don't actually adjust encounter difficulty XP either. They just adjust the difficult name/category, unlike the creature numbers multiplier.)

Right. I agree. My solution, to which I came very early on, was just to ditch XP all together. I use Leveling without Experience[1], following the recommendation to level after ever (approximately) 3 sessions[2]. So much simpler, with so many fewer complications. I may glance at the encounter difficulty tables, but I take them with a huge grain of salt for my particular parties. As expected--DM experience is supposed to trump blind adherence to table values.

[1] Pet peeve--this is not Milestone Leveling. That's a way of granting XP for non-combat-related things (ie story beats). Leveling without Experience does away with XP all together. It'd be fiat leveling except it's on a known cadence. The only caveat I throw is that if a party spends all of their time dinking around (ie not doing anything to move toward any of their goals, self-defined or externally-defined), that session doesn't count. But I've never had to actually impose that penalty.

[2] Less in early T1, plus some variation for when things make sense (ie no leveling during the middle of combat, even if it spans sessions due to timing issues). This is faster than many like, but actually tracks "adventuring days" pretty well IMX. And I don't mind doing pretty fast leveling personally, YMMV.


OTOH expecting that XP awarded should be adjusted for final encounter difficulty (before player activity) is hardly surprising.

If you insist on using XP based entirely on monster encounters, one rule-of-thumb way of adjusting might be like

If you adjust the difficulty label up or down depending on circumstances, also alter the XP awarded up or down to the nearest threshold. So a formerly Hard encounter made Deadly would get the minimum XP (per person) of a Deadly encounter for that level of character, while a Deadly encounter made Hard would get 1 less than the lowest XP for a Deadly encounter.

[Unoriginal]

Though I strongly disagree with your initial set of statements, nor do I find it particularly relevant to the discussion at hand. My assertion was that when attempting to rate the challenge that an encounter will provide, failing to account for tactical considerations will lead to unsatisfactory results. Do you disagree with that assertion at all? More relevantly, the rule of thumb of +- 1 CR per 40 HP, though differing from my methodology in practice and results, seems easy, practical, and testing a few examples results in things "close enough" to my own ad hoc approximations that though I don't have significant experience using that methodology myself it seems sound, especially based on multiple people vouching for it, just fwiw.



Regardless of what you feel CR can or should calculate, from a practical standpoint what a CR is used for is to balance encounters. Saying "CR doesn't cover that" isn't particularly helpful unless you have something else to offer which Does achieve the goal at hand - crafting satisfying encounters. My assertion is that yes, environmental and tactical considerations should absolutely be incorporated when attempting to rate the challenge provided by an encounter. Beyond the sole guidance offered by the DMG in regards to that of increasing or decreasing encounter difficulty by one step per favorable / unfavorable circumstance (which again imho is woefully inadequate guidance but hey at least it's something?), it is my position that attempting to approximate, however loosely, the difference in challenge provided by tactical and environmental considerations will result in crafting more satisfactory encounters than ignoring those considerations entirely. Based on your assertion that it's indisputable they have a huge impact, it would be surprising if you were to disagree with that, so if you have actual advice or guidance to contribute in relation to How to account for that when rating the challenge a monster or encounter will provide, imho that would be more helpful than repeated assertions that CR ignores such things.

It has nothing to do with how I feel. It is a fact stated by the books that CR is not about balancing encounter difficulty, at least by itself.

CR is just a "can the team handle the damage output and can the monster survive for three rounds?" check. Nothing more. You can argue that "Challenge Rating " is not an indicative name for that and that it should be called something else, but that doesn't change what it is and how it's used.


And if it's about the XP calculation, keep in mind that according to the books fighting 400 goblins over an one-year period and fighting 400 goblins in one fight gives the same ammount of XP.

[GiantOctopodes]

But don't adjust CR to do that. You adjust the final difficulty of the encounter. After calculating the base difficulty from creature CR, PC level, and number of enemies, then you adjust the final difficulty for tactical considerations like "enemy flees at half hit points".

Sure, you can. But:
1) I presume someone looking for advice on balancing things is already aware of the loose (imho inadequate) guidance of +/- 1 level of difficulty per advantageous / disadvantageous circumstance
2) That guidance is taken into account in my assertion.

One monster fleeing at half health, one group of monsters having an elevated position, and so forth are things that affect the challenge of that creature disproportionate to the overall increase or decrease in difficulty of the encounter as a whole. Not only as MaxWilson said are the changes in expected combat difficulty not being properly accounted for in adventuring day XP budgets (not to mention treasure rewards, and XP rewards if following 'standard' XP award systems, which are based on monster CRs rather than encounter difficulty) but beyond that, I just don't find that approach to produce satisfactory results.

Attempting to ad hoc roughly how much more or less difficult circumstances make given opponents and adjusting their CR accordingly in my experience produces far more favorable results, from an encounter standpoint and overall from a rewards standpoint (though there are plenty of ways to balance overall gold levels, in my experience having rewards properly reflective of the actual challenge provided by opponents in their lair or whatever is far more satisfying from a player perspective). You'll note that despite that guidance being available, no posters previously suggested the OP reduce the difficulty of the encounter by 1 to account for the one monster fleeing at a certain point - and not just because it's not really warranted in these circumstances, but also because if the OP was targeting a "deadly" encounter, that's not really a viable approach, and even if they're targeting a different difficulty threshold, following that approach is not likely to end with the desired results.

Instead, modifying the amount of the XP budget consumed by the creature in question (by adjusting their CR) and building the encounter differently is more likely to produce the desired results. YMMV, of course, but I know how the DMG says to handle it and I presume the OP does as well. I just think it's bad guidance.

Edit:

It has nothing to do with how I feel. It is a fact stated by the books that CR is not about balancing encounter difficulty, at least by itself.

CR is just a "can the team handle the damage output and can the monster survive for three rounds?" check. Nothing more. You can argue that "Challenge Rating " is not an indicative name for that and that it should be called something else, but that doesn't change what it is and how it's used.


And if it's about the XP calculation, keep in mind that according to the books fighting 400 goblins over an one-year period and fighting 400 goblins in one fight gives the same ammount of XP.

I'm not certain what your point is, or what point of mine you're attempting to address. CR determines monster XP, monster rewards, and forms the foundation for effective encounter building as described in the DMG though, so if it is a fact stated by the books that CR is not about balancing encounter difficulty I'd love to see a quote.

[Tanarii]

In that case, the it becomes necessary to go back and recalculate the new defensive CR as if hit points were adjusted, combine with offensive CR. And the latter is even more complicated if one is less than 1, it isn't as simple as adding them together and dividing by 2, you have to adjust by steps to find the "average".

That really only makes sense if it poofs out somehow, but given how everything isn't really that precise (my own tendency to treat it as if it were besides the point), using it for halved hit points and running away probably isn't the end of the world. (If PCs feel the need to stop runners, it definitely won't be accurate any more than eyeballing the difficulty change though.)

[GiantOctopodes]

In that case, the it becomes necessary to go back and recalculate the new defensive CR as if hit points were adjusted, combine with offensive CR. And the latter is even more complicated if one is less than 1, it isn't as simple as adding them together and dividing by 2, you have to adjust by steps to find the "average".

That really only makes sense if it poofs out somehow, but given how everything isn't really that precise (my own tendency to treat it as if it were besides the point), using it for halved hit points and running away probably isn't the end of the world. (If PCs feel the need to stop runners, it definitely won't be accurate any more than eyeballing the difficulty change though.)

Though this is certainly true, if you feel like doing the legwork, as has been stated by multiple people CRs and difficulties are always going to be fast and loose anyway, and such effort really doesn't seem warranted, which is likely why two different alternate approaches have been proposed which don't rely on exhaustive CR recalculations :smallsmile:

That's certainly a valid approach, but not one I would recommend. Also monsters starting at half health or fleeing at half health as you say doesn't accurately reflect what will happen in reality, so just mho but you're better off treating such enemies as having 75% of their EHP, but that's hardly a meaningful consideration as such small changes are unlikely to matter much in the grand scheme of things anyway since it's all eyeball approximations anyway. The suggestions made have simply been ways to help eyeball moderately more accurately.

[Greywander]

First of all, it appears that what the OP was really asking was how to adjust the XP awarded for defeating this enemy. As suggested by MaxWilson, if it has (essentially) half the HP, then that's half its defensive power, but all of of it's offensive power, making it equivalent to 3/4 of it's normal CR. So you can just award the same XP as a creature of that CR. However, as pointed out by others, the actual CR of the creature doesn't change.

It seems there may have been a misunderstanding of what CR is, with some people reading more into it than there really is. It really is just, "how many hits can it take?" and, "how much damage does it deal?" Anything more nuanced than that becomes too difficult to rate properly. Adjusting the "effective" CR in order to award a different amount of XP is fine, but unless you've actually tweaked the stats of the creature, then the CR stays the same, regardless of the circumstances. Not only has the number of hits it can take and damage it can deal not changed, but certain spells and abilities care about a creature's CR. If you adjust a villain's CR down because they flee at half HP, then you might inadvertently make them more susceptible to one of the spells or abilities of the players. There's also the fact that those tactical concerns might turn on their head; for example, what if the Teleport is Counterspelled? Now the villain has to stand and fight down to its last HP, or else find another way to flee. (Although I'm not sure if Contingency can be Counterspelled, since the actual casting takes place long before the Contingency is triggered. It could probably be Dispelled, though.)

A monster's CR is kind of like a PC's level. A PC doesn't have their level adjusted up or down depending on the tactical consideration. The PCs aren't suddenly lower level when they get ambushed, or higher level when they're the ones ambushing. A PC who fights to the death isn't a higher level than a PC who flees at half HP. However, if you were awarding XP to the monsters, you might decide to award them more XP for taking out the PC who fights to the death than for the one who flees. CR and level are both metrics for (very roughly) gauging the power of a creature, albeit determined in very different ways. Circumstances and tactics may act as a multiplier for that power (and possibly the XP awarded), but the base power level remains the same.

This also highlights how important it is to make sure you're asking the real question. Asking about CR and then saying you're actually asking about XP awarded means that the thread goes off on a tangent about CR before giving you the answers you're looking for. And you know, maybe you didn't know. That's fine, that's why you're asking in the first place. Just clarify what you're asking and don't worry about the tangent. If the thread derails, then start a new thread with your new, clarified question.

[GiantOctopodes]

First of all, it appears that what the OP was really asking was how to adjust the XP awarded for defeating this enemy. As suggested by MaxWilson, if it has (essentially) half the HP, then that's half its defensive power, but all of of it's offensive power, making it equivalent to 3/4 of it's normal CR. So you can just award the same XP as a creature of that CR. However, as pointed out by others, the actual CR of the creature doesn't change.

It seems there may have been a misunderstanding of what CR is, with some people reading more into it than there really is. It really is just, "how many hits can it take?" and, "how much damage does it deal?" 1. Anything more nuanced than that becomes too difficult to rate properly. 2. Adjusting the "effective" CR in order to award a different amount of XP is fine, but unless you've actually tweaked the stats of the creature, then the CR stays the same, regardless of the circumstances. Not only has the number of hits it can take and damage it can deal not changed, but certain spells and abilities care about a creature's CR. 3. If you adjust a villain's CR down because they flee at half HP, then you might inadvertently make them more susceptible to one of the spells or abilities of the players. 4. There's also the fact that those tactical concerns might turn on their head; for example, what if the Teleport is Counterspelled? Now the villain has to stand and fight down to its last HP, or else find another way to flee. (Although I'm not sure if Contingency can be Counterspelled, since the actual casting takes place long before the Contingency is triggered. It could probably be Dispelled, though.)

5. A monster's CR is kind of like a PC's level. A PC doesn't have their level adjusted up or down depending on the tactical consideration. The PCs aren't suddenly lower level when they get ambushed, or higher level when they're the ones ambushing. A PC who fights to the death isn't a higher level than a PC who flees at half HP. 6. However, if you were awarding XP to the monsters, you might decide to award them more XP for taking out the PC who fights to the death than for the one who flees. 7. CR and level are both metrics for (very roughly) gauging the power of a creature, albeit determined in very different ways. Circumstances and tactics may act as a multiplier for that power (and possibly the XP awarded), but the base power level remains the same.

This also highlights how important it is to make sure you're asking the real question. Asking about CR and then saying you're actually asking about XP awarded means that the thread goes off on a tangent about CR before giving you the answers you're looking for. And you know, maybe you didn't know. That's fine, that's why you're asking in the first place. Just clarify what you're asking and don't worry about the tangent. If the thread derails, then start a new thread with your new, clarified question.

Numbers added by me. First, I disagree entirely on what CR is and isn't. CR is used in two ways - 1) to determine monster XP, used to determine the XP budget to build an encounter, as well as additional rough and ready guidance on proper encounter building. 2) To determine rewards, mostly in the form of XP and treasure, reflective of what the players overcame. Those are both baked in wholesale to the systems throughout the DMG and MM. If you want to adjust how you're building encounters, or what kind of rewards are given, you adjust CR, or just wing it and ad hoc it based on broad goals and story beats. Those really are your only two options.

Now, to the specifics of your post:
1. Considering factors like improved invisibility and flight get calculated, I strongly disagree with the idea that things like "are they difficult to get to" are "too nuanced" to rate properly.

2. Nah, it doesn't need to, I'm just fine adjusting CR as I see fit, thanks :smallcool:

3. Sure, but it wouldn't be inadvertent, nor would I particularly care. If you could provide a relevant, impactful example, I'd definitely be interested, as in my experience virtually all effects care about creature's saves, HP, or Hit Dice, not their CR. I'd have far more caution about changing the HD of a monster or its saves than I would adjusting its CR.

4. Absolutely, which doesn't really come into play during encounter building - after all, a creature with a given ability may never find the opportunity to use it, the party can crit on basically everything in the first round and roflstomp an encounter, the enemies can get lucky crits early and an expected stomp can go south fast, plenty can come up on the field which isn't reflected in the creature's initial CR which modulates its difficulty. That's no excuse to handwave everything though - if a creature has a breath weapon and is positioned behind a chokepoint the PCs must approach with a limited number of angles of attack, and the party doesn't have significant ranged abilities, that creature can be expected to be more difficult than if it were on an open field. Again, CR comes in on encounter building and on rewards, you adjust the encounter based on your expectations, and you adjust the rewards based on reality.

5. Nah, a monster's HD is more like a PC's level.

6. And by doing so, you're effectively modifying the CR of the creature in question. As XP rewards, when being granted on a per-monster basis, are directly determined by the CR of the monster in question.

7. If it's a multiplier for XP and / or gold rewarded, it's effectively a multiplier for CR.

[Witty Username]

It is probably recalculate defensive CR with the new HP, calculate the offensive CR. average them. It might get messy. Also I would give full XP if the party does kill/capture the monster in question.
Be confidant that CR is imperfect anyway. Especially if Social/exploration solutions are used for traditionally combat problems.

[Tanarii]

First of all, it appears that what the OP was really asking was how to adjust the XP awarded for defeating this enemy. As suggested by MaxWilson, if it has (essentially) half the HP, then that's half its defensive power, but all of of it's offensive power, making it equivalent to 3/4 of it's normal CR. So you can just award the same XP as a creature of that CR. However, as pointed out by others, the actual CR of the creature doesn't change.
The problem is that halving HP and keeping AC the same doesn't half it's defensive CR. There's a sweet spot around CR 8-12 where it does seem to be the case, or at least close, but it's not universally true.

OTOH until adjusted defensive CR drops below CR1, or starting CR is very high (where assumed AC stays at 19) awarding 3/4 XP is probably close enough, if it's close on offensive CR and defensive CR base. But how many creatures actually are balanced like that, with offensive and defensive CR essentially the same? IIRC not many.

[Yakk]

No it doesn't have to get messy. Like, literally just subtract 1 CR every 32 HP you remove.

Then recalculate proficiency bonus.

(Or don't, proficiency bonus adds about 0,25 CR per point, so skip it).

If HP is still reasonable (like more than 50 ish) that works pretty damb well. You'll be within a half a CR.

This isn't rocket science. The table is pretty clear; 15 points drops defensive CR by 1, 2 defensive CR is 1 CR, and toss on 2 points or so to make up for baseline AC expectation changing.

[Greywander]

First, I disagree entirely on what CR is and isn't. CR is used in two ways - 1) to determine monster XP, used to determine the XP budget to build an encounter, as well as additional rough and ready guidance on proper encounter building. 2) To determine rewards, mostly in the form of XP and treasure, reflective of what the players overcame.
This is not a refutation because the transitive property does not apply here: the CR determines XP and rewards, but the XP and rewards do not determine the CR. The CR is determined by calculating effective HP and effective damage. Then, after you've determined the CR, the XP is set according to that CR.

In other words, you don't just say, "I think monster X is worth Y XP, and a monster worth Y XP is CR Z, therefore, monster X is CR Z." You calculate the monster's effective HP and damage, which then determines CR, which then determines XP. And this is only a guide; you're free as a DM to award a different amount of XP if you want to, but this doesn't retroactively change the creature's CR.


3. Sure, but it wouldn't be inadvertent, nor would I particularly care. If you could provide a relevant, impactful example, I'd definitely be interested, as in my experience virtually all effects care about creature's saves, HP, or Hit Dice, not their CR. I'd have far more caution about changing the HD of a monster or its saves than I would adjusting its CR.
If they, or their ally, has Polymorph, then lowering their CR restricts what they can turn into. There's also the cleric's Destroy Undead, though you'd need to be really low CR to worry about that. Also, the Oathbreaker paladin's Control Undead channel divinity option, where undead with a CR greater than or equal to the paladin's level are immune. It's true there's not a lot of effects that use CR, but they do exist. You also never know what kinds of new abilities might be released in the future that could use CR.


4. Absolutely, which doesn't really come into play during encounter building
And CR is only a very rough guide. Like I've previously said, a monster's CR doesn't change if they're ambushing, or being ambushed. If the situation is weighed against the players, then the DM needs the wisdom to lower the total CR of the encounter to compensate (or not, if they want a deadlier fight), and vice versa if it's weighed in the players' favor. CR simply isn't designed to take these things into account, you need other tools to help you. CR can't do everything; it's a mistake to rely on it too heavily.


5. Nah, a monster's HD is more like a PC's level.
In a way. It generally seems like a creature has an effective level equal to HD-1, e.g. a creature with 2 hit dice is equivalent to a 1st level PC, and a creature with 10 HD is equivalent to a 9th level PC (this is because PCs get max HP from their first HD, while NPCs do not). So HD more accurately tracks as a 1-to-1 comparison to levels. But hit dice only determine hit points; levels both grant hit points and class features. A creature with more hit dice doesn't necessarily have the features or raw stats to back them up. CR is slightly more accurate in measuring power, since it measures effective HP directly (instead of HD, which can be tiny d4s or massive d20s), as well as damage (also, I think proficiency bonus generally tends to track according to CR, not HD). But CR and levels don't have a 1-to-1 comparison, e.g. a CR 20 creature is not equivalent to a 20th level PC.


6. And by doing so, you're effectively modifying the CR of the creature in question. As XP rewards, when being granted on a per-monster basis, are directly determined by the CR of the monster in question.

7. If it's a multiplier for XP and / or gold rewarded, it's effectively a multiplier for CR.
Again, my assertion is that the CR determines XP, not the other way around. CR is only determined by effective HP and damage, so unless you change those, the CR stays the same. Now, once the CR is determined, you can decide that the creature is stronger or weaker because of abilities that don't contribute directly to damage or HP, and arbitrarily shift its CR up or down. But if you're designing a monster (i.e. for a homebrew monster manual), then you need to determine the CR before they appear in a campaign, so tactics and circumstances won't apply. Once the monster appears in a campaign, you, as the DM, can decide to ignore the "XP for CR" system, and award the XP that seems appropriate.

Remember, the DM has final say in everything, and things like CR and XP charts are just tools to help the DM figure things out. This isn't a video game. If a fight seems harder or easier than normal, the onus is on the DM to alter the reward to match. Or not, that's the DM's prerogative. You certainly don't want the PCs intentionally trying to get ambushed so they can get extra XP.

If this still isn't making sense to you, just remember that there are other ways to award XP other than based on CR. There's a system where you determine the difficulty of a fight (easy, medium, hard, or deadly), and then you consult a chart based on the party's level and award the amount in the chart. There's also milestone XP, where you just hand out XP at specific plot points as they advance through the story. Neither of these uses CR to determine XP, but monsters still have a CR.

[MaxWilson]

If this still isn't making sense to you, just remember that there are other ways to award XP other than based on CR. There's a system where you determine the difficulty of a fight (easy, medium, hard, or deadly), and then you consult a chart based on the party's level and award the amount in the chart. There's also milestone XP, where you just hand out XP at specific plot points as they advance through the story. Neither of these uses CR to determine XP, but monsters still have a CR.

This sounds interesting. This isn't a DMG system, so it must be an Internet thing. Do you have a link?

[GiantOctopodes]

This is not a refutation because the transitive property does not apply here: the CR determines XP and rewards, but the XP and rewards do not determine the CR. The CR is determined by calculating effective HP and effective damage. Then, after you've determined the CR, the XP is set according to that CR.

In other words, you don't just say, "I think monster X is worth Y XP, and a monster worth Y XP is CR Z, therefore, monster X is CR Z." You calculate the monster's effective HP and damage, which then determines CR, which then determines XP. And this is only a guide; you're free as a DM to award a different amount of XP if you want to, but this doesn't retroactively change the creature's CR.


If they, or their ally, has Polymorph, then lowering their CR restricts what they can turn into. There's also the cleric's Destroy Undead, though you'd need to be really low CR to worry about that. Also, the Oathbreaker paladin's Control Undead channel divinity option, where undead with a CR greater than or equal to the paladin's level are immune. It's true there's not a lot of effects that use CR, but they do exist. You also never know what kinds of new abilities might be released in the future that could use CR.


And CR is only a very rough guide. Like I've previously said, a monster's CR doesn't change if they're ambushing, or being ambushed. If the situation is weighed against the players, then the DM needs the wisdom to lower the total CR of the encounter to compensate (or not, if they want a deadlier fight), and vice versa if it's weighed in the players' favor. CR simply isn't designed to take these things into account, you need other tools to help you. CR can't do everything; it's a mistake to rely on it too heavily.


In a way. It generally seems like a creature has an effective level equal to HD-1, e.g. a creature with 2 hit dice is equivalent to a 1st level PC, and a creature with 10 HD is equivalent to a 9th level PC (this is because PCs get max HP from their first HD, while NPCs do not). So HD more accurately tracks as a 1-to-1 comparison to levels. But hit dice only determine hit points; levels both grant hit points and class features. A creature with more hit dice doesn't necessarily have the features or raw stats to back them up. CR is slightly more accurate in measuring power, since it measures effective HP directly (instead of HD, which can be tiny d4s or massive d20s), as well as damage (also, I think proficiency bonus generally tends to track according to CR, not HD). But CR and levels don't have a 1-to-1 comparison, e.g. a CR 20 creature is not equivalent to a 20th level PC.


Again, my assertion is that the CR determines XP, not the other way around. CR is only determined by effective HP and damage, so unless you change those, the CR stays the same. Now, once the CR is determined, you can decide that the creature is stronger or weaker because of abilities that don't contribute directly to damage or HP, and arbitrarily shift its CR up or down. But if you're designing a monster (i.e. for a homebrew monster manual), then you need to determine the CR before they appear in a campaign, so tactics and circumstances won't apply. Once the monster appears in a campaign, you, as the DM, can decide to ignore the "XP for CR" system, and award the XP that seems appropriate.

Remember, the DM has final say in everything, and things like CR and XP charts are just tools to help the DM figure things out. This isn't a video game. If a fight seems harder or easier than normal, the onus is on the DM to alter the reward to match. Or not, that's the DM's prerogative. You certainly don't want the PCs intentionally trying to get ambushed so they can get extra XP.

If this still isn't making sense to you, just remember that there are other ways to award XP other than based on CR. There's a system where you determine the difficulty of a fight (easy, medium, hard, or deadly), and then you consult a chart based on the party's level and award the amount in the chart. There's also milestone XP, where you just hand out XP at specific plot points as they advance through the story. Neither of these uses CR to determine XP, but monsters still have a CR.

I'm not going to bother to respond to this post, as it does not meaningfully address any points that I rose. However, I want to be very, very clear about this: The CR system makes sense to me, I understand it perfectly. Despite my understanding of it and comprehension of it, I disagree entirely with your premises and conclusions. Do you have any qualms with that assertion?

[Asisreo1]

There is no encounter budget.

Okay, there is. But that budget isn't the way to create encounters, its only one way.

The default way to create encounters is to use whatever monsters you and your party thinks are cool and fun and put them wherever they make sense. The next step is determining the encounter's difficulty when everything's over. So if a DM wants a CR 15 creature to be in an adventure at level 1, he's at liberty to do so.

If a DM knows what the difficulty of their challenge should be, then they use the budget. Something like them knowing they'll enter a room with a BBEG and they want it to be a hard but not too hard challenge.

[Greywander]

This sounds interesting. This isn't a DMG system, so it must be an Internet thing. Do you have a link?
Page 82 of the DMG. Also, whoops. Look, I saw the table and thought, "this looks useful," and didn't bother reading anything else on the page. That said, even if it's not the intended use, it should totally work to use it this way.

I've also combined this with a sort of milestone XP system before, where every session is worth an easy encounter (so you always get XP every session), and major or minor plot points/quests might be worth encounters of varying difficulty.


I'm not going to bother to respond to this post, as it does not meaningfully address any points that I rose. However, I want to be very, very clear about this: The CR system makes sense to me, I understand it perfectly. Despite my understanding of it and comprehension of it, I disagree entirely with your premises and conclusions. Do you have any qualms with that assertion?
I think where this disagreement is coming from is that I view CR as primarily as a measure of a monster's offensive and defensive power, while XP and rewards are ancillary. If I want to adjust XP or rewards, I do so directly without messing with the CR. But it is true that CR is directly linked to how much XP a monster is worth. You can choose to ignore that, but it's still a thing that exists. So perhaps I'm wrong to dismiss this link. I can certainly see how someone flipping through the MM might come away with the idea that CR is primarily about how much XP the monster is worth, as that's how it appears in the stat blocks.

Ultimately, CR is just a tool. You can use it however you like as long as it's useful to you. It does have its limitations, though, so it shouldn't be relied on too much.

[Unoriginal]

I'm not going to bother to respond to this post, as it does not meaningfully address any points that I rose. However, I want to be very, very clear about this: The CR system makes sense to me, I understand it perfectly. Despite my understanding of it and comprehension of it, I disagree entirely with your premises and conclusions. Do you have any qualms with that assertion?

Look at the "Create a combat encounter" section in the DMG. It *never* talks about monster CRs, except in an aside warning saying "be careful when you use monsters of a CR above the party's level".

For everything else, it talks about the effective XP values and budgets, and while CR is a factor in those they are not the same thing. A Kobold's CR is not modified if one of them is fighting alone against 5 adventurers, only the encounter difficulty and the ammount of XP budget said encounter takes change.