How do you calculate EL?

[Gwazi Magnum]

I always under the impression that a monsters CR was pretty much their level in terms of effectiveness.

So say if you have 4 level 5 players, you could send four level 5 monsters at them and it should be a fair encounter.

Though, looking at the calculators online and some peoples posts... it looks like that's not the case.

So I'm wondering, how exactly does calculating CR and EL work in determining how hard it will be for a group of players or not?

[Stux]

I believe the short answer is that CR is supposed to be about the same as the average level of a party of 4.

It is quite clear that CR does not equate to level directly. Look up for instance the gnoll from the SRD. It's level as a character, before adding any class levels is 3 (2 for racial HD and +1 level adjust), but it's challenge rating is only 1. This means a party of 4 level 1 PCs would find fighting a single gnoll to be averagely difficult - not too hard, not a total push over.

[buttcyst]

the challenge rating system is pretty accurate if you roll you characters up entirely by the RAW (4d6 drop lowest, if all less than 15, reroll line), if your wizard is packing a whopping 13 int, the challenge ratings are appropriate.

Now for the way I do it, I find the relative challenge rating of the party (CR 15 currently), subtract 1 (CR 14), no higher than this number for an outnumbering attack. party level +1 for any minor bosses and +2 for any major bosses. I use the mixed pair rules for a boss and his undelings (CR11 boss + CR 13 underlings = CR 14 encounter).

to raise the EL of a challenge rating, you add things like terrain to your benefit and implement tactics, maybe make some of it dependent on skills (like a portion of it is parley and they have a chance for dip bluf or intim). turn the encounter into a chase, make the bad guys fly and turn invisible.

Also, in the MM tables, the given HP are a median number, do your math and figure out the min-max, you can also adjust feats and skills to suit your needs for the encounter, and many have the option of adding class levels (troll ranger, ogre barbarian, etc...).

The easiest way is to experiment and see how the group does against varying CRs, maybe announce before a particularly tough bad guy that they might die, if they ok with that, let it be, if not, run it anyways and find out, if it's too hard, back it off next time, and you can always dumb it down via DM fiat in the middle of the fight, maybe have him run away and be your BBEG.

[Maginomicon]

You might be better off using the "Level-Independent XP Awards" method (Unearthed Arcana page 213) combined with the Pathfinder method for encounter generation (http://www.d20pfsrd.com/gamemastering) instead of the standard rules . Then you don't have to worry about calculating EL at all, as it's simply a matter of filling a budget of XP with monsters by the experience they give by their CR-alone.

For example, a frost worm (http://www.d20srd.org/srd/monsters/frostWorm.htm) (CR 12) is worth 19,000 XP. If four characters defeat it, they each earn 4,750 XP (19,000 divided by 4), regardless of their level.

Likewise, three ogre mages (http://www.d20srd.org/srd/monsters/ogreMage.htm) (CR 8 each, or 4,800 XP each), five ogres (http://www.d20srd.org/srd/monsters/ogre.htm) (CR 3 each, or 900 XP each), and a dire rat (http://www.d20srd.org/srd/monsters/direRat.htm) (CR 1/3, or 100 XP) are also worth 19,000 XP total.

[Gwazi Magnum]

I believe the short answer is that CR is supposed to be about the same as the average level of a party of 4.

It is quite clear that CR does not equate to level directly. Look up for instance the gnoll from the SRD. It's level as a character, before adding any class levels is 3 (2 for racial HD and +1 level adjust), but it's challenge rating is only 1. This means a party of 4 level 1 PCs would find fighting a single gnoll to be averagely difficult - not too hard, not a total push over.

Yea, I'm honestly surprised I misunderstood the CR system as badly as I did. :/


the challenge rating system is pretty accurate if you roll you characters up entirely by the RAW (4d6 drop lowest, if all less than 15, reroll line), if your wizard is packing a whopping 13 int, the challenge ratings are appropriate.

Now for the way I do it, I find the relative challenge rating of the party (CR 15 currently), subtract 1 (CR 14), no higher than this number for an outnumbering attack. party level +1 for any minor bosses and +2 for any major bosses. I use the mixed pair rules for a boss and his undelings (CR11 boss + CR 13 underlings = CR 14 encounter).

to raise the EL of a challenge rating, you add things like terrain to your benefit and implement tactics, maybe make some of it dependent on skills (like a portion of it is parley and they have a chance for dip bluf or intim). turn the encounter into a chase, make the bad guys fly and turn invisible.

Also, in the MM tables, the given HP are a median number, do your math and figure out the min-max, you can also adjust feats and skills to suit your needs for the encounter, and many have the option of adding class levels (troll ranger, ogre barbarian, etc...).

The easiest way is to experiment and see how the group does against varying CRs, maybe announce before a particularly tough bad guy that they might die, if they ok with that, let it be, if not, run it anyways and find out, if it's too hard, back it off next time, and you can always dumb it down via DM fiat in the middle of the fight, maybe have him run away and be your BBEG.

I like the alteration system according to bosses and such, might be something I'd use.
What happens if it's a group that rolled high, used 32 point buy or something though?

What would appropriate CR boosts be then?


You might be better off using the "Level-Independent XP Awards" method (Unearthed Arcana page 213) combined with the Pathfinder method for encounter generation (http://www.d20pfsrd.com/gamemastering) instead of the standard rules . Then you don't have to worry about calculating EL at all, as it's simply a matter of filling a budget of XP with monsters by the experience they give by their CR-alone.

For example, a frost worm (http://www.d20srd.org/srd/monsters/frostWorm.htm) (CR 12) is worth 19,000 XP. If four characters defeat it, they each earn 4,750 XP (19,000 divided by 4), regardless of their level.

Likewise, three ogre mages (http://www.d20srd.org/srd/monsters/ogreMage.htm) (CR 8 each, or 4,800 XP each), five ogres (http://www.d20srd.org/srd/monsters/ogre.htm) (CR 3 each, or 900 XP each), and a dire rat (http://www.d20srd.org/srd/monsters/direRat.htm) (CR 1/3, or 100 XP) are also worth 19,000 XP total.

This, is a very handy resource.
I will defelently be making use of this in the future if I ever have to plan encounters for people. :)

Thank you very much for this.

[137beth]

Okay, it looks like no one has given you the straight answer:
Under the normal rules for 3.5, by the DMG, a normal encounter for a party of 4 5th level players is one 5th level monster. ONE monster vs FOUR players. If you send four monsters against four players, that is a higher EL.
That is very likely not accurate in your game against your party, but that is what the designers had in mind. Don't rely on it, though.

[Maginomicon]

This, is a very handy resource.
I will defelently be making use of this in the future if I ever have to plan encounters for people. :)

Thank you very much for this.I should mention that the Pathfinder method on its own (that is, without the Level-Independent XP Awards variant) is not necessarily a good substitute for 3.5. Pathfinder functions so significantly different from the way 3.5 works that using PF's encounter generation method strictly on its own will likely result in some odd leveling circumstances for your party.

[Gwazi Magnum]

Okay, it looks like no one has given you the straight answer:
Under the normal rules for 3.5, by the DMG, a normal encounter for a party of 4 5th level players is one 5th level monster. ONE monster vs FOUR players. If you send four monsters against four players, that is a higher EL.
That is very likely not accurate in your game against your party, but that is what the designers had in mind. Don't rely on it, though.

I can recognize that, but in my case at least the group I would end up using it against doesn't optimize.

But, say it wasn't match up, what kind of system would then work to find a balanced encounter?


I should mention that the Pathfinder method on its own (that is, without the Level-Independent XP Awards variant) is not necessarily a good substitute for 3.5. Pathfinder functions so significantly different from the way 3.5 works that using PF's encounter generation method strictly on its own will likely result in some odd leveling circumstances for your party.

It's mostly the CR to XP value conversions I like.
Because that makes it much easier to plan an encounter quickly than having to do the number crunching of different CR pairings.

[TuggyNE]

I always under the impression that a monsters CR was pretty much their level in terms of effectiveness.

So say if you have 4 level 5 players, you could send four level 5 monsters at them and it should be a fair encounter.

This is technically true, but only in the sense that a mirror match is "fair": you have a nominally 50/50 chance of complete defeat on either side. Needless to say, that's not a routine encounter for a party.


So I'm wondering, how exactly does calculating CR and EL work in determining how hard it will be for a group of players or not?

Besides 137ben's explanation, note that every doubling of difficulty increases EL by +2. So one CR 5 monster is an EL 5 encounter; two of them is EL 7, and four of them are EL 9. (EL/CR/level measurements are not linear!)

[Keld Denar]

How do I calculate EL? This handy EL calculator, of course! (http://www.d20srd.org/extras/d20encountercalculator/) As far as planning your adventuring day, the easiest thing to do is to take the effective average party level (APL). A group of 4 PCs is what most of the CRs were balanced around (except for the MMII, which was balanced around 20-30 PCs). So simply take the sum of your party's levels, divide by the number of PCs, and then round it off. If you have 2-3, subtract one from the number, and if you have 5-6, add one. More, and you might need different math. Once you have that number, then you compare it with ELs. An EL = APL encounter takes ~20% of daily resources along with a small amount of non-renewable resources. That means that 4 such encounters in a day is pretty easy, but the 5th starts getting REALLY hard. APL +1 and +2 encounters are also fine and will use up more resources, closer to 30-40%. APL +3 encounters are tough, and APL +4 encounters should be reserved for end boss and other special fights only (like dragons).

[Gwazi Magnum]

This is technically true, but only in the sense that a mirror match is "fair": you have a nominally 50/50 chance of complete defeat on either side. Needless to say, that's not a routine encounter for a party.

Besides 137ben's explanation, note that every doubling of difficulty increases EL by +2. So one CR 5 monster is an EL 5 encounter; two of them is EL 7, and four of them are EL 9. (EL/CR/level measurements are not linear!)

That would explain a lot, though doesn't d&d start to get too easy then if each encounter it designed to be something almost guaranteed for the characters to win? So players end up thinking it's predictable what will happen, it's routine and they'll win no problem?

Also, the CR/EL not being linear is a bit odd and sure does make it harder to figure out. But I think I have it mostly figured out now.

[Tvtyrant]

How do I calculate EL? This handy EL calculator, of course! (http://www.d20srd.org/extras/d20encountercalculator/) As far as planning your adventuring day, the easiest thing to do is to take the effective average party level (APL). A group of 4 PCs is what most of the CRs were balanced around (except for the MMII, which was balanced around 20-30 PCs). So simply take the sum of your party's levels, divide by the number of PCs, and then round it off. If you have 2-3, subtract one from the number, and if you have 5-6, add one. More, and you might need different math. Once you have that number, then you compare it with ELs. An EL = APL encounter takes ~20% of daily resources along with a small amount of non-renewable resources. That means that 4 such encounters in a day is pretty easy, but the 5th starts getting REALLY hard. APL +1 and +2 encounters are also fine and will use up more resources, closer to 30-40%. APL +3 encounters are tough, and APL +4 encounters should be reserved for end boss and other special fights only (like dragons).
Don't do that! I choked on my popcorn while laughing :smallyuk: Seriously though, it hurt...

Although some encounters that are supposed to take 20% end up taking none. Like my party killing a group of locathahs at level 1 without using any spells (reserve feats for the casters) and taking no damage. 2 are supposed to be a threat to the whole party, and instead I was chucking groups of 6 to do anything :C

[tyckspoon]

That would explain a lot, though doesn't d&d start to get too easy then if each encounter it designed to be something almost guaranteed for the characters to win? So players end up thinking it's predictable what will happen, it's routine and they'll win no problem?

Also, the CR/EL not being linear is a bit odd and sure does make it harder to figure out. But I think I have it mostly figured out now.

Well, power per level is not linear for PCs either (especially for spellcasters, who get a significant jump in power every time they get access to a new spell level), so why should the encounter difficulty metrics be?

As far as 'routine' encounters go.. that is a complaint that has been aimed at the system. I think it stems from a misunderstanding of what the CR system actually advocates- you're not supposed to have all your encounters be on-level CR/ECL. IIRC the book actually suggests that only about 50% of encounters your party has be of of equal CR, with the rest in a spread of both over and under party level fights.

[TuggyNE]

That would explain a lot, though doesn't d&d start to get too easy then if each encounter it designed to be something almost guaranteed for the characters to win? So players end up thinking it's predictable what will happen, it's routine and they'll win no problem?

Each fight is supposed to cost them some resources, and have a small but significant chance of dying; it's only once the adventuring day is nearing its end that the chance of death should generally go up much.

The alternative design choice is to make characters die every few fights, which gets expensive and tedious very quickly. Given that the point of the game is for the characters to win in the end, you pretty much have to math it out so that the probability of failure or serious setbacks is fairly low most of the time, or else iterative probability from multiple fights will ruin things. (For example, a 20% chance of someone dying in any given fight means that you have a ~11% chance of getting through ten fights with a whole party, and <67% chance of getting through those fights with at least half a four-man party surviving.)

[137beth]

I can recognize that, but in my case at least the group I would end up using it against doesn't optimize.

But, say it wasn't match up, what kind of system would then work to find a balanced encounter?
Only your judgement is good enough for estimating encounter difficulty. You know your players and their strengths and weaknesses, we do not. If you aren't sure about a particular encounter, I suggest that you play-test it with your player's character sheets.

[Gwazi Magnum]

Well, power per level is not linear for PCs either (especially for spellcasters, who get a significant jump in power every time they get access to a new spell level), so why should the encounter difficulty metrics be?

As far as 'routine' encounters go.. that is a complaint that has been aimed at the system. I think it stems from a misunderstanding of what the CR system actually advocates- you're not supposed to have all your encounters be on-level CR/ECL. IIRC the book actually suggests that only about 50% of encounters your party has be of of equal CR, with the rest in a spread of both over and under party level fights.

I get that not all I meant to be equal CR. The concern is that it may get too easy for the players though.


Each fight is supposed to cost them some resources, and have a small but significant chance of dying; it's only once the adventuring day is nearing its end that the chance of death should generally go up much.

The alternative design choice is to make characters die every few fights, which gets expensive and tedious very quickly. Given that the point of the game is for the characters to win in the end, you pretty much have to math it out so that the probability of failure or serious setbacks is fairly low most of the time, or else iterative probability from multiple fights will ruin things. (For example, a 20% chance of someone dying in any given fight means that you have a ~11% chance of getting through ten fights with a whole party, and <67% chance of getting through those fights with at least half a four-man party surviving.)

I agree that the should be about the players and the DM vs Player aspect is only one to take if you want the group to end.

Note I come from a group that never understood this system so almost every encounter ended up being a challenging one with a good chance of death. But I'm concerned if the encounters are designed to be lost and just sap some resources the players may get bored because of the minimal risk or danger.

But I suppose I could still throw a really hard one or two at them to keep them on their toes.


Only your judgement is good enough for estimating encounter difficulty. You know your players and their strengths and weaknesses, we do not. If you aren't sure about a particular encounter, I suggest that you play-test it with your player's character sheets.

Good point in the play testing.

[Urpriest]

I agree that the should be about the players and the DM vs Player aspect is only one to take if you want the group to end.

Note I come from a group that never understood this system so almost every encounter ended up being a challenging one with a good chance of death. But I'm concerned if the encounters are designed to be lost and just sap some resources the players may get bored because of the minimal risk or danger.

But I suppose I could still throw a really hard one or two at them to keep them on their toes.


Yeah, the main point is that each encounter takes a quarter of the players' resources, so that by the end of the day they're on the edge. No one encounter is supposed to take all their resources/kill people unless it's a boss fight.

[ksbsnowowl]

Keld Denar already posted it, but I just want to reiterate using the d20 Encounter Calculator (http://www.d20srd.org/extras/d20encountercalculator/). It saves you time in calculating XP awards, and in just messing around with ideas (what if I pair these two monsters together... what would the EL be?)

Absolutely great resource that I would hate to be without.

[Gwazi Magnum]

Yeah, the main point is that each encounter takes a quarter of the players' resources, so that by the end of the day they're on the edge. No one encounter is supposed to take all their resources/kill people unless it's a boss fight.

True, it would be interesting to deal with CR appropriate encounters for a change.


Keld Denar already posted it, but I just want to reiterate using the d20 Encounter Calculator (http://www.d20srd.org/extras/d20encountercalculator/). It saves you time in calculating XP awards, and in just messing around with ideas (what if I pair these two monsters together... what would the EL be?)

Absolutely great resource that I would hate to be without.

True, that does also work.
Though personally the XP buy system from 4th and Pathfinder was always a system I preferred.