High Quality Content by WIKIPEDIA articles! A chess rating system is a system used in chess to calculate an estimate of the strength of the player, based on his performance versus other players. They are used by organizations such as FIDE, the US Chess Federation (USCF), International Correspondence Chess Federation, and the English Chess Federation. Most of the systems are used to recalculate ratings after a tournament or match but some are used to recalculate ratings after individual games. In almost all systems a higher number indicates a stronger player. In general, a player`s rating goes up if he performs better than expected and down if he performs worse than expected. The magnitude of the change depends on the rating of his opponents. The Elo rating system is currently the most widely-used.