EXtreme Gammon


eXtreme Gammon is backgammon software written by Xavier Dufaure de Citres and released in 2009. It is available for Microsoft Windows and mobile platforms.
According to the Financial Times, the program is the best backgammon player in the world, and the near-exclusive study tool for all serious backgammon players.

Performance rating

eXtreme Gammon provides a widely accepted benchmark number for players' skills called the Performance Rating or PR, with a lower number indicating a better rating. PR is the average equity lost per decision multiplied by 500. Only decisions not considered to be "obvious" are counted.
PRDescriptionELO equivalent
0.0-2.5World Champ2162-2240
2.5-5.0World Class2077-2162
5.0-7.5Expert1986-2077
7.5-12.5Advanced1792-1986
12.5-17.5Intermediate1593-1792
17.5-22.5Casual Player1405-1593
22.5-30.0Beginner1167-1405
30.0 or moreDistracted1167 or less