Elo Rating Calculator

Elo Rating Calculator. Enter your current Elo rating, your opponent's Elo rating, the game result (Win, Draw, or Loss), and the K-factor to calculate your new Elo rating and rating change. The Elo Rating Calculator also shows your expected score probability against the opponent, so you always know what the system predicted before you played. Also try the Slugging Percentage Calculator.

Your current Elo rating before the game.

Your opponent's current Elo rating.

Select the outcome of the game from your perspective.

K-factor controls how much your rating changes per game. FIDE uses 40 for new players, 20 for most adults.

Results

New Rating

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Rating Change

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Expected Score

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Actual Score

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Opponent's New Rating

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What is the Elo rating system?

The Elo rating system is a method for calculating the relative skill level of players in zero-sum games like chess. Developed by Arpad Elo — a Hungarian-American chess player and physics professor — it assigns each player a numeric rating. Beating a higher-rated opponent earns you more points than beating a lower-rated one, while your opponent loses exactly as many points as you gain. See also our calculate True Shooting Percentage (TS%), True Shooting Attempts (TSA) & Shooting Efficiency Rating — True Shooting Percentage (Basketball).

How is Elo rating change calculated?

The change is calculated using the formula: ΔR = K × (S − E), where K is the K-factor, S is your actual score (1 for win, 0.5 for draw, 0 for loss), and E is your expected score. The expected score is E = 1 / (1 + 10^((opponent_rating − your_rating) / 400)). A bigger rating gap means a more 'surprising' result yields a larger change.

What is the K-factor and how do I choose it?

The K-factor determines the maximum rating change per game. FIDE uses K=40 for new players (first 30 games), K=20 for most adult players, and K=10 for elite players above 2400. A higher K-factor means your rating reacts more dramatically to results, which is appropriate for newer players whose true strength is still uncertain.

Is 1000 Elo good in chess?

A 1000 Elo rating is considered beginner level in chess. Most casual players who have learned the rules but haven't studied much theory fall in the 800–1200 range. An average club player typically sits around 1500, and a national-level amateur around 1800–2000.

What is considered a high Elo in chess?

Ratings above 2000 are considered strong amateur level. Elo 2200+ earns the title of FIDE Candidate Master, 2300+ is FIDE Master, 2400+ is International Master, and 2500+ is Grandmaster. Magnus Carlsen's peak rating of 2882 is the highest ever recorded.

Does my opponent lose the same points I gain?

Yes — in the standard Elo system, the rating points are conserved. Whatever points you gain, your opponent loses the same amount. This is what makes Elo a 'zero-sum' system. Both players' ratings are updated simultaneously after each game.

Can the Elo system be used outside chess?

Absolutely. The Elo system is widely used in many competitive contexts including online gaming (League of Legends, FIFA Ultimate Team), table tennis, go, competitive programming, and even academic paper ranking. Any head-to-head competition with a clear winner can be modeled with Elo.

What happens to my Elo if I beat a much weaker opponent?

Beating a significantly weaker opponent earns very few rating points because the win was already highly expected. For example, if you are rated 1800 and beat a 1200-rated player, you might only gain 1–2 points. The system rewards upsets — beating a much stronger player — with a larger gain. You might also find our calculate eFG (Basketball) Effective Field Goal % (eFG%) useful.