The official international chess rating system used by FIDE worldwide.
This calculator uses the official FIDE ELO rating formula. Enter your current rating, your opponent's rating, select the game result, and see how your rating would change.
If you don't have an ELO rating, the system estimates a starting rating based on your results against rated opponents. FIDE rules require a sufficient number of valid games against rated opponents for an initial rating. Opponents without ELO or with invalid ratings are included in the tournament score but may not count toward the rating calculation.
Expected Score:
New Rating:
K-Factor determines the maximum possible rating change per game. FIDE uses K=40 for new players (under 30 games), K=20 for players rated below 2400, and K=10 for players rated 2400+.
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