Dungeons and Dragons Monsters – Adjusting CRs

Behind the Screen – Dungeons and Dragons Monsters – Adjusting CRs

Behind the Screen is an article series designed to give information to the Dungeon Masters/Game Master. So they can make an informed decision on what campaign they want to play next.

As DMs we all hit the monsters are “too easy” or “too hard” complaing from our players. I have talked with several other DMs and discovered that most of us are not using the CR (Challenge Ratings) to our advantage. In the below article I will go over how to handle CRs (both too easy and too hard), loot calculation, and possible fixes for the group. (Outside of throwing Purple Worms and Terrasques at them until they have to make new characters)

What is a CR?

The CR is based on a party of 4 (keep this in mind), that means a party of 4 Level 1 Characters should easily be able to handle a monster of level 1, or 4 monsters CR 1/4, or 8  monsters CR 1/8, or…….you get the picture. This calculation was based on some heavy play testing from Wizards of the Coast and has been adjusted through the years. XP (Experience Point) gains are based on the CR, so if have to adjust the CR for any reason we have to adjust both the XP and loot that the players get.

Monsters with CRs above the party level (wich is the average level of the party members) increase the chance of death for the party at an exponential level. Monster with a CR 2 facing a party of average level 1, should be difficult and possibly deadly (not counting the min/maxers in your group). A CR 4 Monster though, should be extremely deadly and cause your party to thinking about running. Finally a CR 8 Monster, against the same group, should cause them to run in fear.

Calculating a CR

Over the editions since 3E (when CR was first started being used), the formula has changed. Here are the peices we need:

  • Party Level (PL) – Average of the PC levels
  • Monster CR (Pulled from the Monster Description)

Calculating the Party Level 

Add all the levels of the PCs up and divide by the number of PCs Round Down.

Example:

Group of 4 PCs with the following Levels 2,1,3 and 4. Party Level is (2+1+3+4)/ 4 = 2.5 => 2

That means they should facing CR monsters of 2 or less Without any problems. If that number had been 2.6 then the Party level would have been 3.

This will hold true from number of PCs from 1 to 4. It is when we get above 4 party members that the calculation gets weird.

Calculating a CR for a Large Group

DM having to deal with 6+ groups is not unheard of, we all get together with our friends and love playing. Soon we have more people playing than what we expected and poof our PL is skewed. Or Maybe we have a person that wants to try out the game and just wants to play. Either way we need to adjust our PL and CR for the encounters that the players face.

Thankfully 3E went over this well and still hold true to day. For my example I will use a party of 6, though this holds true for any number in the party. My Example has 6 PCs with the levels ( 1,3,4,5,2,1)

First order the PC levels from lowest to highest, so my example would be 1,1,2,3,4,5. Then the average the first 4, this is our base party level. So (1 + 1 + 2 +3) / 4 = 1.75 => 2  now since both the next levels are above 2, we adjust the PL by +1.

PL (2 +1) =3. Since both are above 3 we adjust it by 1 again Giving us PL 3+1 = 4. So our PL for our Party is 4. if the other 2 PCs were Level 3 and 3 we would adjust it just by 1 but since they were much higher we had to adjust it again. Clear as mud right?

Think of it this way, if we were just playing with the 4 and the 5 their average PL would be (4+5) /2 = 4.5 => 4, which means they would easily dispatch any CR 3 monsters. So adding the additional +1 allows for them to have a risk also without completely putting the entire party at risk.

Alternate Method

We could order them from least to greatest again and then group them by 4 people and find the PL seperately, it would look something like this:

  • Group A : (1,1,2,3) PL 2
  • Group B : (4,5) PL 4

Then add the PLs together and divide by the number of groups, giving us the overall PL of the party.

(2+4)/2 = PL 4

For a group of 10 with the PC at (1,1,3,4,5,6,1,2,3,4) this would look like:

(1,1,1,2,3,3,4,4,5,6)

  • Group A: (1,1,1,2) PL 1
  • Group B: (3,3,4,4) PL 3
  • Group C: (5,6) PL 5

Overal PL would Be (1+3+5) /3 = PL 3.

I will go over how to make the game more interesting next and adjusting loot gain next.

CR Adjustments and Fixes

Smaller groups are easy to adjust for by reducing the number of monsters encounter to the CR equaling the PL. Keep in mind that some of those higher monsters can have some abilities that might tip the scale. For larger parties think of multiple enemies equating to the CR. For the example above with 10 people I might throw, 30 CR 1/10 at them. or 12 CR 1/4 at them to keep them engaged.

This can also be a bit of work for a DM to keep track of all initiatives for the monsters, so I usually group them in lots of 4 and roll initiative for each group. That way the party doesn’t know when my monsters are going to go and the monsters have a fighting chance against them.

Remember either way you will want to keep the PL in mind when checking your loot tables on pages 136 to 139 in the Dungeon Master’s Guide. This can be adjusted by the PL Grouping we did above, for a CR 3 monster group I would roll for the PL 1 group, then the PL 3 Group, and finally the PL 5 Group on the charts. Just to Equate out loot better.

Summoning it all up

Dealing with large parties can be interesting. I once helped DM for a group of 24 people back in 2E, we had to break out everything into 3 groups of 8 just to keep it going for the weekend with a culminating event of everyone at the end on Sunday. It was fun, it was hard, and I would probably not do it again. It was also an experience that made me appreciate the CR system in 3E and beyond.

As always if you have questions, suggestions, or concerns leave a comment below.

-Archon Del Noche

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Dungeons and Dragons Monsters – Adjusting CRs
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