Elo Rating Calculator

After a chess match or any head-to-head game, this tool tells you the Elo rating you walk away with. Tracking that swing is how players measure progress, spot the holes in their game, and plan their approach to upcoming tournaments. FIDE's rating regulations, in force since 1 March 2024, use the same idea: they read an expected score from a table and multiply the difference between your actual and expected score by a K-factor.

Elo is a way to express the relative skill of players in competitor-versus-competitor games as a single number. The standard formula used here pulls together your current rating, your opponent's rating, the result of the game (win, loss, or draw), and a K-factor. Your expected score is 1 ÷ (1 + 10^((opponent − you) ÷ 400)), and the change is K × (actual score − expected score), rounded to a whole point. The K-factor caps how far a single game can move your rating: FIDE uses 40, 20 or 10 depending on a player's experience, age and rating, while the calculator starts at 32 and lets you enter your own federation's value.

Beating someone rated well below you rarely moves the needle much, so don't expect a lopsided win to send your rating soaring; the gain is usually slim. Dropping a game to that same lower-rated player, on the other hand, can cost you a noticeable chunk. The K-factor sits at the center of all this: newer or lower-rated players carry a higher one, which makes their ratings swing more sharply from game to game.