EXtreme Gammon

eXtreme Gammon is backgammon software written by Xavier Dufaure de Citres and released in 2009.^[1] 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.^[1]

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. ^[1][2]

eXtreme Gammon Performance Ratings

PR	Description	ELO equivalent
0.0-2.5	World Champ	2162-2240
2.5-5.0	World Class	2077-2162
5.0-7.5	Expert	1986-2077
7.5-12.5	Advanced	1792-1986
12.5-17.5	Intermediate	1593-1792
17.5-22.5	Casual Player	1405-1593
22.5-30.0	Beginner	1167-1405
30.0 or more	Distracted	1167 or less