GlenCalc

Elo rating calculator

The Elo system moves ratings by how surprising a result is. Beating a stronger player gains more than beating a weaker one.

How fast ratings move. FIDE uses 40 for new players, 20 for most, 10 for the top.

Your answer

Your new rating1,611.5+11.5
Opponent’s new rating1,488.5
Your expected score64% chance-weighted0.64

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How we worked it out

Updated as you change the numbers.

  1. Expected score E = 1 ÷ (1 + 10^((opponent − you) ÷ 400)).
  2. New rating = old rating + K × (result − E), with result 1, ½ or 0.

Method and assumptions

A 400-point gap means the stronger player is expected to score about 91%. Ratings are zero-sum between the two players when both use the same K.

Questions

How much does a 1600 player gain by beating a 1500 player?

11.5 points with K = 32: the expected score was 0.64.

Sources

Method and figures checked on . Every worked answer on this page is covered by an automated test. Found a mistake? Tell us.

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