FIDE Rating Delta
Applies the Elo formula to your rating, the opponent rating, the game result and the K factor, returning points gained or lost and the new rating.
Delta + new rating
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FIDE rating delta and the Elo system
The Elo system, created by Arpad Elo in 1959 and adopted by FIDE in 1970, updates ratings by the difference between actual and expected score: ΔR = K · (score − expected), where expected = 1 / (1 + 10^((R_opp − R_you)/400)). The K factor controls volatility — FIDE uses K=40 for newcomers (fewer than 30 games), K=20 for established players and K=10 for titled players (2400+). Reference brackets: 2400+ Grandmaster (GM), 2700+ super-GM, 2800+ elite (Magnus Carlsen, Fabiano Caruana, Hikaru Nakamura). FIDE publishes official ratings monthly.
Applications
Competitive chess at FIDE and national federations (CBX in Brazil), online platforms like Lichess and Chess.com (with their own K factors and Glicko-2 variants), Go, tennis (ATP rankings use a different formula but the same logic), MMA (UFC and analytics sites), and most modern e-sports matchmaking systems are Elo-derived.
FAQ
Why is a 400-point difference special? By formula, 400 points means a ~91% expected score for the favorite. Two players 400 points apart playing a draw is essentially a major upset.
Why are Lichess ratings inflated? Lichess uses Glicko-2 with a different scale; ratings there typically run 200–400 points above FIDE for the same player.
Can my rating drop after a win? No — wins are always non-negative. But beating a much weaker opponent yields only a fraction of a point.
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The results provided by this tool are for general informational and educational purposes only and do not constitute professional, financial, medical, legal, tax or accounting advice. Always confirm important decisions with a qualified professional and official sources.