# Calculating effective party level



## thorian (Aug 11, 2007)

When trying to determine an appropriate encounter level for a party, the formula for the effective party level is fairly simple if there are 4 characters -- you take the average of the 4 character's levels and determine the effective party level.  How is the formula different for parties that are not comprised of 4 characters?


----------



## Jack99 (Aug 11, 2007)

for 3 6th level characters
3 times 6 = 18.
18 divided by 4 = 4.5

for 5 6th level characters
5 times 6 = 30
30 divided by 4 = 7.5

Dont forget that other things can affect the ECL of characters. 32+ point buy is +1 ECL (arguably), also if they have an aboundance of magic items (read much more than the average values), you should bump the ECL by one as well.


----------



## TessarrianDM (Aug 11, 2007)

Jack99 said:
			
		

> for 3 6th level characters
> 3 times 6 = 18.
> 18 divided by 4 = 4.5
> 
> ...




So, my party of 3-14th, 5-13th and one 10th level characters has an ECL of 29.25 and not the 15.5 as calculated by the penpaperpixel.org Encounter Calculator? That just sounds way too high, considering that they have a hard time with encounters in the CR 20 range. When I plan encounters using the 15.5 figure that the Encounter Calculator gave me , they seem to be more appropriate challenges for the level (a little low from a "use up 25% of party resources per encounter" standpoint, but I can work with that).

The encounter calculator I use is at penpaperpixel.org/tools/d20encountercalculator (sorry, not computer literate enough to post a link  ). I believe there are others out there that are available for free (search for d20 encounter calculators). It has definitely reduced my encounter planning headaches.


----------



## irdeggman (Aug 11, 2007)

Jack99 said:
			
		

> for 3 6th level characters
> 3 times 6 = 18.
> 18 divided by 4 = 4.5
> 
> ...





Not really the method to be used.

I asked Skip (the Sage) that one a while ago since our group was about 7-8 PCs.

The "correct" method is to use the EL tables (with mixed pairs) and back it out.

The "simple" method is to calculate the avg (total ECL/total # of characters) and then add 1 for every additional 2 PCs (over 4). But round down.

My house rules were the simple method and a note to ensure that no single CR exceeded the highest ECL character by more than 2. Also the specifics had to be looked at to ensure that the CR creature could axtually be "hurt" by what the PCs had available. Ensuring that the party could cast spells of appropriate level, etc.)


----------



## Thurbane (Aug 12, 2007)

I always find this site extremely useful:

d20 Encounter Calculator


----------



## thorian (Aug 12, 2007)

Thurbane said:
			
		

> I always find this site extremely useful:
> 
> d20 Encounter Calculator



That is actually the site that caused my question.  I was wondering how they calculated the result.


----------



## Nifft (Aug 12, 2007)

thorian said:
			
		

> That is actually the site that caused my question.  I was wondering how they calculated the result.




The script that contains their formulas is here:
http://www.penpaperpixel.org/scripts/encounterCalculator.js

Cheers, -- N


----------



## Thurbane (Aug 12, 2007)

I suspect it just adds up total levels and divides by number of members, but check the script to be sure.


----------



## Ogrork the Mighty (Aug 12, 2007)

There are EL generators out there. I'd use one of those.


----------



## blargney the second (Aug 12, 2007)

I like Cheiromancer's system:
1) Square each PC's level.
2) Add all those squares together.
3) Take the square root of that sum.
4) Divide it by 2 to get the effective average party level.

Example:
6 PC's levels {6,7,7,8,9,10}
1) Squares {36, 49, 49, 64, 81, 100}
2) Sum squares {379}
3) Square root {19.5}
4} Divide by 2 for effective party level {9.8}

So a single high CR 9 or low CR 10 should take up 1/4 of the party's resources, all things being equal.
-blarg


----------



## Quartz (Aug 12, 2007)

Cross-checking against *TessarianDM*'s group, I get an EPL of 17.3 for *Cheiromancer*'s system.


----------



## Jack99 (Aug 12, 2007)

TessarrianDM said:
			
		

> So, my party of 3-14th, 5-13th and one 10th level characters has an ECL of 29.25 and not the 15.5 as calculated by the penpaperpixel.org Encounter Calculator? That just sounds way too high, considering that they have a hard time with encounters in the CR 20 range. When I plan encounters using the 15.5 figure that the Encounter Calculator gave me , they seem to be more appropriate challenges for the level (a little low from a "use up 25% of party resources per encounter" standpoint, but I can work with that).
> 
> The encounter calculator I use is at penpaperpixel.org/tools/d20encountercalculator (sorry, not computer literate enough to post a link  ). I believe there are others out there that are available for free (search for d20 encounter calculators). It has definitely reduced my encounter planning headaches.




Hmm yeah, not really well thought out. Sorry about that. I usually just eyeball the encounters, and was trying to be helpful. Guess I should have given it some more thought before I posted it.

/hangs head in shame.


----------



## Li Shenron (Aug 12, 2007)

Calculate average normally, use normal EL for 4, then multiply the number of monsters proportionally.

Ex. 6 PC instead of 4? Create the encounter with normal CR or EL, then add +50% more monsters.

Works fine except for single BBEG, which cannot easily be multiplied


----------



## Hussar (Aug 12, 2007)

Li Shenron is wise.  You should listen to the words.  

With larger parties it's always better to use more critters than bigger ones.  While a large party does have lots of firepower, individual members don't have the staying power of a higher level character.  So, if you simply plonk down a bigger critter, instead of two PC's getting chewed, you get one PC dead as a full attack will drop him in a single round.

Makes BBEG fights a bit trickier, but, instead of using a bigger boss, just include lots of mooks.  Makes for a slower fight usually, but, also usually more interesting as different tactical issues come into play.


----------



## gnfnrf (Aug 12, 2007)

thorian said:
			
		

> When trying to determine an appropriate encounter level for a party, the formula for the effective party level is fairly simple if there are 4 characters -- you take the average of the 4 character's levels and determine the effective party level.  How is the formula different for parties that are not comprised of 4 characters?




I use the same rule as for ELs.  Double the PCs = +2 effective party level.  Since most parties don't come in multiples of 4, I interpolate logarithmically.

Thus, take the average party level then add (excel code for clarity) LOG(N/4, 2)*2, where N is the party size.

This works well for parties in the 5-8 range.  I haven't tried it for small parties or very very large parties.  

I also third the single foe problem with balancing large party ELs.  They are either too fragile or two powerful, sometimes both at once.

--
gnfnrf


----------



## blargney the second (Aug 12, 2007)

Li Shenron's given the best advice so far.


----------

