Chess Elo Rating Difference Calculator

This section will calculate the difference in Elo rating between two players from match results or winning percentage. It uses javascript to do the calculations.

Wins Losses Draws
PointsGames
/
Winning percentage

Elo difference :

Elo Rating Change Calculator

This section will calculate the change in a player's Elo rating after playing a single game against another player. The value K is the maximum change in rating.

Player Elo   : K :
Against Elo :

Win Draw Loss

Expected Percentage :

Wikipedia Elo
see for details on the formula used for the calculations. (You can also right click on this page and View Page Source to see my Javascript code.)

Slow Chess Blitz
my freeware chess program.