Challenge Rating Explained

[blackjack50]

So I tend to have relatively underpowered NPCs in my game. Mostly because the players I’ve played with are newer and I am still new to DMing. So. With that said, I’d like a little help on CR.

I get the basic concept. It is when one starts to throw in multiple enemies that I get lost. So here is my understanding. Please tell me if I am off base:

CR3 Enemy = A challenge for 4 players Level 3

(Here is where I am lost)

CR 1 + CR 2 Enemy = CR3 Enemy (roughly)

4 CR 1/4 Enemy + 2 CR1 Enemy = CR3 Enemy (roughly)



Is this the appropriate formula I should be using? Or is there a different variation for groups?

[Cheesegear]

Is this the appropriate formula I should be using? Or is there a different variation for groups?

Encounters get more difficult the more hostiles there are in the encounter, because the players' action economy is still fixed. A Level 3 Fighter, who hasn't got Extra Attack yet, finds fighting two easier hostiles, much harder than fighting one single hostile, even if those hostiles have a lower individual CR. And then when he does have Extra Attack, 3 hostiles is harder than 2, etc.

The DMG, on page 82, gives you the table used to calculate the modifier for CR on encounters that contain more than one hostile.


CR 1 + CR 2 Enemy = CR3 Enemy (roughly)

Actually, it'd be CR4.5


4 CR 1/4 Enemy + 2 CR1 Enemy = CR3 Enemy (roughly)

A CR3 group containing 6 hostiles, would actually be an encounter CR6.

[blackjack50]

Encounters get more difficult the more hostiles there are in the encounter, because the players' action economy is still fixed. A Level 3 Fighter, who hasn't got Extra Attack yet, finds fighting two easier hostiles, much harder than fighting one single hostile, even if those hostiles have a lower individual CR. And then when he does have Extra Attack, 3 hostiles is harder than 2, etc.

The DMG, on page 82, gives you the table used to calculate the modifier for CR on encounters that contain more than one hostile.



Actually, it'd be CR4.5



A CR3 group containing 6 hostiles, would actually be an encounter CR6.

Thank you so much for that. I’m going to bookmark that (literally) and here on the web lol.

[CapnWildefyr]

Using CR is kind of "iffy" but it seems OK to me so far as a guide. Just learn what a CR3 means to Your group--start out lighter and see what happens, make encounters harder/weaker as needed for your table so they are challenged but not wiped out. And like Cheesegear said, in reality there is somewhat more sensitivity to quantity than quality than given in the formula (when the CRs are close-- several CR1s vs 1 CR3 you can gang up on, or whatever).

[Demonslayer666]

I second what Cheesegear said.

And add that when the party faces one big monster that they will focus fire on it and make it a much easier encounter, and able to handle much higher CRs.

This is a tricky balance, because not only does it depend on your player's characters abilities, but also how they play them. My players tend to trivialize deadly encounters, so I have to ramp it up for them.

[MaxWilson]

Is this the appropriate formula I should be using? Or is there a different variation for groups?

No, use the DMG formulas. In fact, use the Kobold.club implementation of the DMG formulas because it does all the math for you: https://kobold.club/fight/

[Undyne]

If you have Xanathars Guide Or the DMG, both have tables to calculate challange rating for the opponents. I prefer Xanathars Guide because it accounts for the power spike at each tier.

[Nidgit]

Comparing how your party deals with a "CR appropriate" encounter is important as a starting point. That scale ends up changing as time goes on too- things tend to be a bit swingier before Level 3 or 4, so it's better to avoid too many enemies. At higher levels, your party will typically have an easy time with an encounter that's the same CR they are. You should have a better idea of their abilities by then though.

[Man_Over_Game]

Using CR is kind of "iffy" but it seems OK to me so far as a guide. Just learn what a CR3 means to Your group--start out lighter and see what happens, make encounters harder/weaker as needed for your table so they are challenged but not wiped out. And like Cheesegear said, in reality there is somewhat more sensitivity to quantity than quality than given in the formula (when the CRs are close-- several CR1s vs 1 CR3 you can gang up on, or whatever).

I agree. CR doesn't really feel precise.

Although a good rule of thumb I've found is just to figure out the average HP and damage per level, and make budgets out of those.

Average Player HP: 4 + (7*Level)

Average Player Damage-per-round: 10 + (2*level)

Multiply those values by the number of players you have to get the party's total damage per turn (Td) and health (Th).

Have a target length of combat (about 3 rounds is good), which we'll use as R.

Enemy Total Damage per turn = Th / R

Enemy total HP = Td * R.

It's better to guess R as being lower, as there's going to be about a 35% chance to miss at all levels, meaning estimating a 3 round combat is going to actually take about 4 rounds.




Using example numbers:


Party Members: 4
Party Level: 6
Party Max Health estimate: (4 + (7 * 6)) * 4 = 184
Party Damage-per-turn estimate: (10 + (2 * 6)) * 4 = 88



Combat length: 3-4 rounds (using 3, which will generally round up)




Enemy team damage per turn: 184 / 3 = 61.3
Enemy team total HP: 88 * 3 = 264



So create an enemy team that deals about 61 damage per turn and has a total of 264 HP.

It's also important that a player should rarely lose all of their HP in a single turn. The average HP of a character at this level is 46, but shaving a little off the top (to account for wizards) brings us to 30. No creature at this level should be dealing more than 30 average damage in a single turn (but a single creature can get around this and do more damage in a round via Legendary Actions or Lair Actions).

It's better to base your numbers off of estimated averages of party values rather than real party values. Otherwise, as your team makes investments to get tankier, enemies will deal more damage, and none of your players' decisions will hold weight. A team of mages should feel squishy, rather than feeling like their enemies are armed with limp noodles.