Chess Elo Calculator
Estimate your expected score and rating change after a win, draw or loss.
A larger K-factor produces larger changes. This is a generic Elo estimate, not an official FIDE, Chess.com or Lichess rating calculation.
Expected score
This includes draws worth half a point. It is not the probability of winning.
| Result | Change | New rating |
|---|---|---|
| Win | +15.19 | 1515.19 |
| Draw | +5.19 | 1505.19 |
| Loss | -4.81 | 1495.19 |
E = 1 / (1 + 10^((opponent − you) / 400))
New rating = rating + K × (result − E). Display rounded to two decimals.
Understand the estimate
Enter both ratings and a K-factor. The calculator shows the generic Elo expected score and the change for each result. For two players rated 1500 with K=20, a win adds 10 points, a draw changes nothing, and a loss subtracts 10.
Expected score includes draws
A 50% expected score means an average of half a point per game across comparable encounters. It does not mean an exact 50% chance of winning a single game. Wins score one point and draws score half a point in the formula.
Which rating system does this use?
This is a generic Elo calculation. It does not implement the official FIDE tables and complete rating regulations, nor the Glicko systems used by online platforms. Do not interpret it as an exact forecast of a platform’s next rating update. See Lichess’s explanation of rating systems.
For worked examples, read how Elo rating changes work.