Math Equation help request - I'm brain-freezing...

[Henry]

...The general rule about estimating the Encounter Level for a Challenge is increase the EL by +2 if you double the number of creatures. Last night I tried to express this as a formula to solve for the number of creatures, and I brain-froze. What I got was:

n=((EL-CR)/2)^2

where n=number of creatures, CR is challenge rating for the individual creature, and EL is the desired encounter level. However, it doesn't work for all desired EL's. I know I'm going to have some fractional amounts for n in some instances, but it's still coming up wrong on simple values like making an EL9 encounter out of CR 1 creatures.

Now, accuracy of the game mechanics aside (that's another discussion), I'm just trying to express this such that, for designing a dungeon, I can have a quick formula to look at and do in my head rather than a chart. Can someone please rescue me from my math atrophy?

 

[Vraister]

n=2^((EL-CR)/2) should work!

Vraister

 

[Henry]

(slaps forhead)

See where I screwed up now!

Thank you!

 

[skitleer]

n=2^((EL-CR)/2)

edit : oops too late

 

[dcollins]

I have a collected document of "Math Formulas for D&D", including the equivalent of this one, on this page here: http://superdan.net.home.comcast.net/dnd3.html

The simplest solution to fractional CRs is to convert them to negative CRs, as done in that document.

 

[Kae'Yoss]

Argh! Leave me alone with your mathematics. It burns, it burns.