FIDE Rating Calculator
Enter your FIDE rating and the games you played. You get the rating change and your new rating, worked out the way FIDE does it, game by game.
K 20: 30 or more games, rated under 2400.
The games rated on one monthly list, each with your opponent's FIDE rating.
Score 3 of 5, expected 2.01. K 20 × 0.99 = 19.80, rounded to +20.
| # | Opponent | Result | Expected | Change |
|---|---|---|---|---|
| 1 | 1792 | Win | 0.58 | +8.40 |
| 2 | 1911 | Draw | 0.42 | +1.60 |
| 3 | 2010 | Loss | 0.29 | -5.80 |
| 4 | 2290* | Draw | 0.08 | +8.40 |
| 5 | 1745 | Win | 0.64 | +7.20 |
* More than 400 points away, so counted as 400 away (the 400-point rule): 2290 as 2250.
Worked example
A player rated 1850 has K 20: more than 30 rated games, never a published rating of 2400, and past the year they turned 18. In one month they play five standard games. These are the games the calculator above opens with.
| Opponent | Difference | Expected | Result | Score − expected |
|---|---|---|---|---|
| 1792 | +58 | 0.58 | Win (1) | +0.42 |
| 1911 | -61 | 0.42 | Draw (0.5) | +0.08 |
| 2010 | -160 | 0.29 | Loss (0) | -0.29 |
| 2290 | -400* | 0.08 | Draw (0.5) | +0.42 |
| 1745 | +105 | 0.64 | Win (1) | +0.36 |
The five differences add up to 0.99. Multiplied by K 20, that is 19.80, which FIDE rounds to +20, so the new rating is 1870.
* Game 4 shows the 400-point rule. The opponent is 440 points higher, but for a player rated below 2650 the difference counts as 400, so the expected score is 0.08 rather than 0.06.
How FIDE calculates a rating change
- For each game against a rated opponent, take the rating difference D: your rating minus your opponent's.
- In standard chess, if you are rated below 2650, a difference of more than 400 points counts as 400. In rapid and blitz it counts as 400 for everyone.
- Read your expected score PD from FIDE's table below. It is the higher-rated player's figure if D is positive and the lower-rated player's if it is negative.
- Subtract PD from your result: 1 for a win, 0.5 for a draw, 0 for a loss.
- Add those differences up for every game rated in the month and multiply by your K factor. Round the total to a whole number, 0.5 away from zero.
The K factor
- 40 until you have completed events with at least 30 rated games.
- 40 for every player until the end of the year of their 18th birthday, as long as their rating stays under 2300.
- 10 once your published rating has reached 2400, even if it later drops below 2400.
- 20 for everyone else, as long as the rating stays under 2400.
- If K times the number of games in one month would be more than 700, K becomes the largest whole number that keeps it at 700 or less. With K 40, that starts at 18 games.
The regulations list these rules without ranking them. Where two could apply, the calculator follows their wording, and your FIDE profile shows the K that FIDE actually uses: if it differs, set it by hand.
FIDE's conversion table
FIDE does not use the 1 / (1 + 10−D/400) formula that most Elo calculators use. It reads the expected score from this table (section 8.1.2), whose figures differ from that formula by up to 0.015 within 400 points.
| Difference D | Higher rated | Lower rated |
|---|---|---|
| 0–3 | 0.50 | 0.50 |
| 4–10 | 0.51 | 0.49 |
| 11–17 | 0.52 | 0.48 |
| 18–25 | 0.53 | 0.47 |
| 26–32 | 0.54 | 0.46 |
| 33–39 | 0.55 | 0.45 |
| 40–46 | 0.56 | 0.44 |
| 47–53 | 0.57 | 0.43 |
| 54–61 | 0.58 | 0.42 |
| 62–68 | 0.59 | 0.41 |
| 69–76 | 0.60 | 0.40 |
| 77–83 | 0.61 | 0.39 |
| 84–91 | 0.62 | 0.38 |
| 92–98 | 0.63 | 0.37 |
| 99–106 | 0.64 | 0.36 |
| 107–113 | 0.65 | 0.35 |
| 114–121 | 0.66 | 0.34 |
| 122–129 | 0.67 | 0.33 |
| 130–137 | 0.68 | 0.32 |
| 138–145 | 0.69 | 0.31 |
| 146–153 | 0.70 | 0.30 |
| 154–162 | 0.71 | 0.29 |
| 163–170 | 0.72 | 0.28 |
| 171–179 | 0.73 | 0.27 |
| 180–188 | 0.74 | 0.26 |
| 189–197 | 0.75 | 0.25 |
| Difference D | Higher rated | Lower rated |
|---|---|---|
| 198–206 | 0.76 | 0.24 |
| 207–215 | 0.77 | 0.23 |
| 216–225 | 0.78 | 0.22 |
| 226–235 | 0.79 | 0.21 |
| 236–245 | 0.80 | 0.20 |
| 246–256 | 0.81 | 0.19 |
| 257–267 | 0.82 | 0.18 |
| 268–278 | 0.83 | 0.17 |
| 279–290 | 0.84 | 0.16 |
| 291–302 | 0.85 | 0.15 |
| 303–315 | 0.86 | 0.14 |
| 316–328 | 0.87 | 0.13 |
| 329–344 | 0.88 | 0.12 |
| 345–357 | 0.89 | 0.11 |
| 358–374 | 0.90 | 0.10 |
| 375–391 | 0.91 | 0.09 |
| 392–411 | 0.92 | 0.08 |
| 412–432 | 0.93 | 0.07 |
| 433–456 | 0.94 | 0.06 |
| 457–484 | 0.95 | 0.05 |
| 485–517 | 0.96 | 0.04 |
| 518–559 | 0.97 | 0.03 |
| 560–619 | 0.98 | 0.02 |
| 620–735 | 0.99 | 0.01 |
| over 735 | 1.00 | 0.00 |
What this calculator does not cover
- A first rating. An unrated player needs at least 5 games against rated opponents, and the first rating is worked out from the opponents' average with two imaginary 1800 opponents added, up to a maximum of 2200 (section 8.2). This calculator is for players who already have one.
- The 1400 floor. FIDE lists only ratings of 1400 and above, so the calculator takes ratings from 1400. A player who drops below 1400 is shown as unrated on the next list, and the calculator says so.
- The one-off increase of 1 March 2024. Ratings under 2000 rose by 0.4 × (2000 − rating) that day. It is already part of every published rating, so nothing here applies it again.
- Games against unrated players. They do not change a rated player's rating, so the calculator asks only for rated opponents.
Source: the FIDE Rating Regulations effective from 1 March 2024, sections 8.1 to 8.3, including the change to the 400-point rule effective from 1 October 2025, and the FIDE Rapid and Blitz Rating Regulations, section 7.3. Read on 23 October 2026, and checked against five of FIDE's own published rating calculations.
Playing in the United States? The USCF rating calculator estimates a US Chess rating, and the Elo calculator shows the win probability and rating change for a single game.
FIDE rating calculator FAQ
How is a FIDE rating change calculated?
For each game, FIDE takes the difference between your rating and your opponent's, reads your expected score from its conversion table, and subtracts it from your result (1 for a win, 0.5 for a draw, 0 for a loss). Those differences are added up for the month and multiplied by your K factor. The total is rounded to a whole number, with 0.5 rounded away from zero.
What is my FIDE K factor?
K is 40 until you have played 30 rated games, and 40 for every player until the end of the year they turn 18, as long as their rating stays under 2300. It is 10 once your published rating has reached 2400, even if it drops again, and 20 for everyone else. If K times the number of games in one month would be more than 700, K is lowered until it is not. Your current K is shown on your FIDE profile.
What is the 400-point rule?
In standard chess, a rating difference of more than 400 points counts as 400 for a player rated below 2650. Since 1 October 2025, players rated 2650 and above use the real difference. In rapid and blitz the 400-point rule applies to everyone, and since 1 December 2024 a game between players 600 or more points apart is not rated if either of them is rated above 2600.
When will my new FIDE rating be published?
FIDE publishes a rating list on the first day of every month. A tournament that ends at least three days before a list can be rated on it, once the federation has sent in the tournament report.
Why does this differ from a plain Elo calculator?
Most Elo calculators work out the expected score with the formula 1 / (1 + 10^(-D/400)). FIDE reads it from its own table instead, and the two differ by up to 0.015 per game within 400 points. FIDE also adds up the whole month before rounding, and counts a rating gap of more than 400 points as 400 (in standard chess, only for players rated below 2650).
Does this work if I do not have a FIDE rating yet?
No. A first FIDE rating needs at least 5 games against rated opponents, and it is worked out differently: the average rating of your opponents, counting two imaginary opponents rated 1800 that you drew with, adjusted up or down for how well you scored, up to a maximum of 2200. This calculator is for players who already have a rating.