ELO

The ELO rating system is a method for calculating the relative skill levels of players in competitor-versus-competitor games such as chess. A player's ELO rating is represented by a number, which increases or decreases based upon the outcome of games between rated players. After every game, the winning player takes points from the losing one. The total number of points gained or lost after a game is determined by the difference between the ratings of the winner and loser. In a game between a high-rated player and a low-rated player, the high-rated player is expected to score more points. If the high-rated player wins, only a few rating points will be taken from the low-rated player. However, if the lower rated player scores an upset win, many rating points will be transferred. The lower rated player will also gain a few points from the higher rated player in the event of a draw.

ELO rating categories

2400+Grandmaster
2300–2400International Master
2200–2300Candidate Master
2000–2200Expert
1800–2000Class A
1600–1800Class B
1400–1600Class C
1200–1400Class D
below 1200Novice
You start with ELO = 1500.