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Elo Calculator

Calculate updated Elo ratings for chess and sports after any match result.

Reviewed October 7, 2026 Runs in your browser — inputs are never stored

Elo Calculator

Player A New Rating

1512

+11.5

Player B New Rating

1388

-11.5

Win probability for A: 64.0%

Ratings before and after the game
  • Player A — before1500
  • Player A — after1512
  • Player B — before1400
  • Player B — after1388

This tool provides general sports and fitness estimates for educational purposes only. It is not medical advice — consult a physician before starting or intensifying training, especially if you have a cardiovascular condition.

About the Elo Calculator

The Elo calculator updates two players’ ratings after a game. The expected score for A is 1 ÷ (1 + 10^((Rb − Ra) ÷ 400)), and each rating changes by K × (actual − expected). Beating a stronger opponent earns more points than beating a weaker one. Chess federations and many games use variations of the system.

How to use it

  1. 1Enter both players’ ratings.
  2. 2Choose the result from Player A’s point of view.
  3. 3Choose the K-factor and read the new ratings.

Worked example

a 1,500-rated player beating a 1,400-rated player has an expected score of 0.64, so with K = 32 they gain about 11.5 points.

Common use cases

  • Chess clubs and tournaments
  • Ranking players in leagues
  • Game rating systems

Frequently asked questions

A:A method for calculating relative skill. 200-point difference = ~75% win probability for the higher-rated player.

Reviewed for accuracy · Last updated October 7, 2026

Formulas follow published sports-science literature and official league definitions (Karvonen heart rate reserve, Cooper and Bruce protocols, MET compendium values, and standard baseball, cricket, and basketball statistics).

CW

CalcWisee Editorial Team

Calculator development and formula review

CalcWisee is an independent site founded by Ayman. Every calculator is built from a published formula or official definition, tested against hand-worked examples before it goes live, and corrected promptly when a reader reports an issue to ayman@calcwisee.com.

Expertise: Financial mathematics, Health and fitness formulas, Applied mathematics, Unit conversion standards

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