Board Game Arena

I have a question about ELO calculation for multiplaer games.
FAQ says it is calculated as if there were separate 2-player games agsinst every opponent. But what I actually observe contradicts that.

For 3 player game, if I win, I am awarded about 75% of points I'd have received in two separate games (individual ELO awards can be seen in details, and they don't sum up to total award).

So... what is the actual algorithm used?

For 3+ player games there's simply a scaling factor like the 75% you observed. The factor varies somewhat by (game+player count) combination but for the most part I think I see 60-80% for 3-4 player games. I don't think there's an explicit list of the factors anywhere but it'd be cool if someone wanted to spend the time to look at completed games and figure it out.

The scaling factor is based on number of players as follows:

a/(2b-2)

Where b is number of players and a is the lesser of number of players and the ‘bga best player count’


So as long as bga best count >= number players…

At 3 the factor is 75%.
For 4 it’d be 67%

Thank You very much, now everything fits