About the Elo Rating Calculator
New Elo ratings after a game, with expected score and rating change for both players.
Also known as: elo rating change, chess rating calculator, elo formula, rating change.
How to use this calculator
- Enter your rating, opponent rating, result, k-factor.
- The result updates instantly as you type — press Calculate (or Enter) at any time.
- Review the breakdown shown under the main result.
- Use Copy result or Share to save the answer or send a link with your inputs.
Elo Rating formula
New = old + K × (score − expected) · expected = 1 / (1 + 10^((Rb − Ra)/400))
Worked example
Using the values pre-filled in the calculator above:
- Your rating = 1,500
- Opponent rating = 1,620
- Result: Win
- K-factor = 20
the calculator returns:
- New rating: 1,513
- Rating change: +13.3
- Expected score: 33.4%
- Opponent’s new rating: 1,607