Chess rating calculator
This calculator estimates how your FIDE rating changes after a set of games. It reads the expected score for each game from the Handbook table, multiplies the gap between your points and the expected points by your K factor, and rounds to a whole number. An Elo formula view sits beside it.
Your rating before these games, 0 to 3000.
A whole number, 0 to 10,000. It decides whether you count as a new player.
Has not finished the calendar year of the 18th birthday.
Example: the starting numbers, a win against an equal-rated opponent. Type your own rating and games to see your result.
- Rating change
- +10
- New rating 1,810
- Exact change before rounding
- 10.00
- Score and expected score
- 1 of 1, expected 0.50
- Expected score is the points the rating gaps say you should score.
- K factor
- K = 20
- K sets how far one game can move your rating. Rated below 2400 and never above.
FIDE Handbook B02 8.3.1, B02 8.1.2, B02 8.3.3, edition 1 March 2024, checked 2026-10-19
| Game | Opponent | Result | Gap used | Expected |
|---|---|---|---|---|
| 1 | 1,800 | Win | 0 | 0.50 |
How the rating change is computed
FIDE compares what you scored with what your rating said you should score. Each game has an expected score, read from the Handbook table for the gap between the two ratings. The change is K times the difference between your points and the expected points, rounded to a whole number.
Change = K x (points scored - sum of expected scores)
The gap between the ratings is capped at 400 points before the table is read, except for players rated 2650 or higher, who use the full gap.
Which K applies
| Situation | K |
|---|---|
| Fewer than 30 games on your rating list | 40 |
| Under 18 and rated below 2300 | 40 |
| Rated 2400 or higher at any point, even if the rating later drops | 10 |
| Rated below 2400 and never above | 20 |
When K times the number of games would pass 700, K is lowered to the largest whole number that keeps the product within 700.
Worked examples
These rows were produced by the same code as the calculator above. Set the calculator to the same inputs and you will see the same numbers.
| Game | Calculation | Expected | Exact change | Change |
|---|---|---|---|---|
| Win against an equal rating (1800) | FIDE table | 0.50 | 10.00 | +10 |
| Win against an equal rating (1800) | Elo formula | 0.5000 | 10.000 | +10 |
| Draw against a lower rating (1700) | FIDE table | 0.64 | -2.80 | -3 |
| Draw against a lower rating (1700) | Elo formula | 0.6401 | -2.801 | -3 |
| Loss against a higher rating (2000) | FIDE table | 0.24 | -4.80 | -5 |
| Loss against a higher rating (2000) | Elo formula | 0.2403 | -4.805 | -5 |
FIDE table or the Elo formula
The Handbook publishes a table of expected scores by rating gap, and that table is what FIDE uses. The textbook Elo formula, 1 / (1 + 10^(-gap / 400)), gives almost the same curve but no cap and no rounding in steps. Both views are here so you can compare them.
Expected score = 1 / (1 + 10 ^ (-(your rating - opponent rating) / 400))
Sources
Checked against the FIDE Handbook edition dated 1 March 2024 on 2026-10-19. Expected scores: B02 8.1.2. K factor: B02 8.3.3. Rating gap cap: B02 8.3.1. FIDE Handbook.
Rating periods, minimum games and publication rules for the official list are in the same chapter of the Handbook. Only FIDE's published list is official.
Questions people ask
- Is this my official FIDE rating?
- No. It estimates the change from the games you enter, using the Handbook rules, treating them as one rating period. Only the list FIDE publishes is official, and it can differ if your games fall in different periods or an event was rated in a special way.
- Why does my K factor change?
- K depends on how many games you have on the list, your age and whether your rating has ever reached 2400. A higher K moves your rating faster. The tool states which rule it applied and what K it used, so you can check it against your own record.
- Will this match my online rating?
- No. Online sites run their own rating systems, so their changes follow different rules. Use the Elo formula view as a textbook comparison, and keep the FIDE view for games that FIDE rates, such as over-the-board classical events.
- How many games can I enter?
- Up to 20 games in one rating period. The tool uses your rating before the first game for every game in the list, which is how the Handbook treats the games of a single period. Enter games from separate periods one period at a time.
Want a plan for the games behind the numbers?
The first lesson reviews your games, reads your level and ends with a written study plan.