Chess ratings are numerical values that represent a player's skill level in the game of chess. These ratings are calculated based on a player's performance in matches against other rated players. The most common rating system is the Elo rating system, which adjusts a player's rating after each game, depending on the outcome and the ratings of the opponents. A higher rating indicates a stronger player, while a lower rating suggests a less experienced player. Ratings can fluctuate significantly based on recent performance, making them a dynamic measure of a player's current abilities. Many chess organizations, including FIDE (the International Chess Federation), maintain official ratings for players worldwide.