Chess ELO Rating Change Calculator
Use this calculator to determine how many FIDE ELO rating points you will gain or lose after a chess game, based on your current rating, your opponent's rating, the appropriate K-factor, and the game result.
Understanding Chess ELO Calculations
The ELO rating system is a method for calculating the relative skill levels of players in zero-sum games such as chess. It is named after its creator Arpad Elo, a Hungarian-American physics professor.
Your rating only changes when you actually play a rated game. The amount it changes depends on three main factors:
- The difference in ratings: You gain more points for beating a higher-rated player than a lower-rated player. Conversely, you lose more points if you lose to a lower-rated player.
- The result of the game: Whether you won (1), drew (0.5), or lost (0).
- The K-Factor: This is a coefficient that determines how drastically a rating can change in a single game. FIDE (the international chess federation) uses different K-factors depending on a player's experience and rating level.
- K=40: For new players until they have completed at least 30 rated games, or until their 18th birthday if their rating remains under 2300.
- K=20: The standard factor for most players whose rating has never exceeded 2400.
- K=10: For elite players whose rating has reached 2400 or higher. Once a player reaches K=10, it does not increase again even if their rating drops below 2400.
Example Calculation
Let's assume the following scenario:
- Your Rating: 1500
- Opponent's Rating: 1600
- K-Factor: 20 (Standard)
- Result: You Win the game.
Because your opponent is rated 100 points higher than you, your "expected score" is lower than 50%. If you achieve a win (scoring 1.0), you have significantly exceeded expectations.
Using the calculator above, a 1500 player beating a 1600 player with a K-factor of 20 would result in a rating change of roughly +13 points, bringing their new rating to 1513.