Chess Expected Score Calculator
Enter two Elo ratings to see the expected score per game and the expected points over a match, using the standard Elo formula.
Formula
E = 1 / (1 + 10^((Ropponent − Rplayer) / 400))
E is your expected score per game: 0.50 with equal ratings, about 0.64 with a 100-point advantage. It counts a draw as half a point, so it is the average of wins and half-draws — not a pure win probability. Expected points over a match are simply E × number of games.
Expected score by rating advantage
| Rating advantage | Expected score | Points per 10 games |
|---|---|---|
| 0 | 0.50 | 5.0 |
| +100 | 0.64 | 6.4 |
| +200 | 0.76 | 7.6 |
| +300 | 0.85 | 8.5 |
| +400 | 0.91 | 9.1 |
The table is symmetric: the underdog's expected score is 1 − E, so a 200-point underdog is expected to make 2.4 points out of 10.
Frequently asked questions
Is expected score the same as win probability?
No — draws count as half a point. An expected score of 0.64 could mean winning 64% of games with no draws, or winning far fewer with many draws. At higher levels draws are common, so the true win percentage is usually below the expected score.
What are my chances against a much stronger player?
At +400 for the opponent your expected score is 0.09 — about one point in eleven games. The formula never reaches zero: even against a giant rating gap you are expected to score occasionally.
Does this use the FIDE 400-point rule?
No. This page shows the raw formula at any rating difference. FIDE caps the difference at 400 points only when calculating rating changes — see the Elo change calculator for that.
Learn more in the guide: How FIDE Ratings Work