How to work out Party CR

[Valkyrie-Storm]

Hi there, I have started a campaign recently and I'm trying to work out party CR, I don't understand how do I work it out for say 6 Level 1 Characters is the party CR 1 so I can only have 1 CR Monster for it to be a normal challenge or can I have say 4 Monsters of CR 1 for it to still be a fair and normal challenge?

[Arcaian]

CR is quite a... vague area, in that two monsters of equal CR can be vastly different in challenge, depending on both the monsters and your party.

Your party does technically have a CR, but CR is the challenge rating for an enemy - so your party's CR is only calculated if you want them to be the enemies. You want to calculate the average player level (APL) of your party, and compare it to the enemies challenge rating. The APL for a party of purely level 1s, is of course 1. However, due to having 6 players - these numbers presume 4 - you add one to the APL, making it 2. If you give them an enemy with a CR = 2, then it's an average encounter. It should be pretty easy really, and expend roughly 1/4 of their daily resources - spells and the like. CR = 3 is one above their APL, written as APL + 1. This is a more difficult encounter, but certainly possible. APL + 3 is considered 'epic level' in the books, but you can normally face one per day for an average party, and it's fine. APL + 4 is what you'd get if you made them fight their 'duplicates' - say an evil, but otherwise identical copy of the party. It should be a very close fight, and use almost all their daily resources. You should be careful to go above APL + 4 - it gets difficult. If you give your players an advantage - e.g. better terrain, enemy is in a spot that's bad for them, you can lower the CR of the encounter by 1, or the opposite is true for giving your players a disadvantage.

The CR of an encounter depends on the amount of mosnters, definitely. 4 CR1 monsters is equal to a CR 5 challenge - for your party listed, it is an APL + 3 encounter and so is fair game for quite a big fight for the day. It would give them about ~300 exp each, out of a total 2000 to get to 2nd level, and so is a fairly substantial fight.

More information can be found here:
http://paizo.com/pathfinderRPG/prd/gamemastering.html

Note: In a normal game, the CR system is often not very effective at predicting difficulty for the party if they're reasonably well optimized. Semi-experienced players can probably win a APL+4 encounter most of the time, and APL+3 encounters twice in a day, most likely.

[Ring_of_Gyges]

Technically, a CR 1 creature is supposed to deplete about a quarter of the resources of a party of four level 1 PCs. The party should be able to handle four fights like that before they need to rest and recover spells, hp, 1/day smite evils, etc...

For 6 PCs I'd suggest increasing the CR of the monsters by 1. So, a CR 2 monster is a minor threat the party should be able to overcome four times before running out of resources.

CR 3 and 4 monsters are more serious threats, but should be manageable if they don't come too frequently.

CR 5 and 6 monsters have a decent chance of killing at least a couple PCs and should be used very sparingly.

CR 7 or more and you're probably looking at everyone dying.

It's a rough guide, picking monsters in more art than science. With experience you'll develop a feel for what your PCs can handle pretty quickly. When in doubt it is safer to throw weaker monsters at the party than stronger, it's a lot easier to move the story forward if the PCs stomp a pair of goblins than if they're eaten by a dozen trolls.

[GM 1990]

If you're just getting started its worth sticking to APL+1 encounters for a bit to feel out your players tactics and such.

Additionally, there are a couple things like paralyze that come up pretty early (wights) that can devastate the group in just a couple hits. Ogres are also deceptively deadly for only CR3. They're +7 to hit, and 2d8+7 damage. That'll on average put down even a 1st level fighter in 1 hit (avg of 16 points of damage). (and have a 10ft reach so they threaten a large area)

I've found my current group who used 4x6 method of stat generation is essentially a +1 to their APL, since it turned out to be nearly a 30pt buy array for most of them. They've consistently tackled APL+3 with no issues, but +4 often puts 1 or more PC unconscious. Just shows how narrow it can be sometimes bumping the CR up just by 1 - a lot of that is due to the d20 random effect. When the CR is tight to max the variance can tip the scales very fast on a crit for the monsters.

Also, when designing your encounter, if you have them fighting 1 monster, its going to be a little weaker than you expect because the group is focusing all of its actions vs 1. So the group may be able to take on a little more difficult monster if its solo.

I tend to mix up 2 or more, and include something using ranged attacks. it just adds depth to the encounter and allows the group to use things like their bows, ranged spells, and charge actions.

[Deadalready]

The (unofficial) way I calculate the party's CR equivalent is:

Add all character levels up, divide by 4.
+1 if they have 25 point buy
+1 if they have more wealth than Wealth Balance Per Level

However as level 1s just just go with a CR battle of 1 and occasionally 2 and see how they fair. Beginner characters are generally still finding their feet and won't be overpowering.

Edit: Also there are plenty of monsters who do not belong in their CR levels, ranking much higher than their CR would suggest.