Elo Rating Calculator
Instantly calculate rating changes for chess, esports, or competitive matchmaking using the official Elo formula.
Match Details
New Ratings
Expected Win Probabilities
How does the Elo calculation work?
The Elo rating system, originally invented by Arpad Elo for chess, calculates the relative skill levels of players in competitive games. After every match, the winning player takes points from the losing player. The number of points transferred depends entirely on the difference in their initial ratings.
If a high-rated player defeats a low-rated player, only a few points are exchanged, because the system expected that outcome. However, if a low-rated player pulls off an upset against a grandmaster, a massive amount of points are transferred to reward the underdog.
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