You finish a tournament, check the standings and wonder: how many points am I going to gain (or lose)? The FIDE rating system looks complicated at first, but it comes down to one idea: you are compared to what you were expected to score. Score more than expected and your rating goes up. Score less and it goes down.
This post explains how FIDE calculates standard (classical) ratings under the FIDE Rating Regulations in force since 1 March 2024, including the amendment of 1 October 2025. It works through a complete tournament example and then covers the special cases.
The formula in one line
For every rated game:
ΔR = score − PD
- score is your result: 1 for a win, 0.5 for a draw, 0 for a loss.
- PD is your expected score, the probability FIDE assigns to you based on the rating difference between you and your opponent.
Add up the ΔR of all your games in the rating period, then multiply by your K-factor:
Rating change = K × Σ(score − PD)
The result is rounded to the nearest whole number and added to your rating on the next monthly list.
Step 1: Find your expected score (PD)
FIDE doesn’t use a calculator formula for PD. It uses an official lookup table: you find the rating difference D between you and your opponent and read off the expected score for the higher-rated (H) and lower-rated (L) player. Here’s a shortened version:
| Rating difference (D) | PD higher-rated | PD lower-rated |
|---|---|---|
| 0–3 | 0.50 | 0.50 |
| 26–32 | 0.54 | 0.46 |
| 54–61 | 0.58 | 0.42 |
| 84–91 | 0.62 | 0.38 |
| 99–106 | 0.64 | 0.36 |
| 130–137 | 0.68 | 0.32 |
| 163–170 | 0.72 | 0.28 |
| 198–206 | 0.76 | 0.24 |
| 257–267 | 0.82 | 0.18 |
| 303–315 | 0.86 | 0.14 |
| 392–411 | 0.92 | 0.08 |
| 412–432 | 0.93 | 0.07 |
The full table has one row for every hundredth of expected score. It is in section 8.1.2 of the regulations.
Tip: The table closely follows the logistic formula
PD = 1 / (1 + 10^(−D/400)). It’s fine for a quick estimate, but official calculations always use the table, and the two can differ by 0.01 now and then.
Notice that the two columns always add up to 1.00. Between two players, the points one is expected to win are the points the other is expected to lose.
Step 2: Know your K-factor
K controls how fast your rating moves. FIDE uses these values:
| K | Who it applies to |
|---|---|
| 40 | New players, until they have completed events totalling at least 30 games |
| 40 | All players until the end of the year of their 18th birthday, as long as their rating stays under 2300 |
| 20 | Everyone else rated under 2400 |
| 10 | Players whose published rating has reached 2400, permanently, even if they later drop below 2400 |
A higher K means bigger swings. That’s why juniors and new players move so quickly: their rating is still “finding its level”.
A worked example
Meet Maria. She is 34 years old, has played hundreds of rated games and is rated 1850, so her K-factor is 20. She plays a 7-round Swiss open:
| Round | Opponent | Opp. rating | Result |
|---|---|---|---|
| 1 | Player A | 1720 | Win |
| 2 | Player B | 2015 | Loss |
| 3 | Player C | unrated | Win |
| 4 | Player D | 1905 | Draw |
| 5 | Player E | 1420 | Win |
| 6 | Player F | unrated | Loss |
| 7 | Player G | 1790 | Win |
Maria scored 5/7 on the crosstable. For her rating, though, only some of these games count.
Remove the games that don’t count
Rounds 3 and 6 were against unrated players, so they are not rated for Maria. The regulations only compute a rated player’s change “for each game played against a rated player”. Her win in round 3 earns her nothing, and her loss in round 6 costs her nothing. (Both games do count for her unrated opponents, as we’ll see below.)
That leaves 5 rated games.
Calculate ΔR for each rated game
Round 1: win vs 1720. D = 1850 − 1720 = 130. Maria is the higher-rated player, so PD = 0.68. ΔR = 1 − 0.68 = +0.32
Round 2: loss vs 2015. D = 2015 − 1850 = 165. Maria is the lower-rated player, so PD = 0.28. ΔR = 0 − 0.28 = −0.28
Round 4: draw vs 1905. D = 55, lower-rated, so PD = 0.42. ΔR = 0.5 − 0.42 = +0.08
Round 5: win vs 1420. The real difference is 430 points, but under the 400-point rule (explained below) it is counted as 400. D = 400, higher-rated, so PD = 0.92. ΔR = 1 − 0.92 = +0.08 (Without the cap, PD would be 0.93 and Maria would get only +0.07.)
Round 7: win vs 1790. D = 60, higher-rated, so PD = 0.58. ΔR = 1 − 0.58 = +0.42
Add up and multiply by K
| Round | Score | PD | ΔR |
|---|---|---|---|
| 1 | 1 | 0.68 | +0.32 |
| 2 | 0 | 0.28 | −0.28 |
| 4 | 0.5 | 0.42 | +0.08 |
| 5 | 1 | 0.92 | +0.08 |
| 7 | 1 | 0.58 | +0.42 |
| Total | 3.5 | 2.88 | +0.62 |
Rating change = K × ΣΔR = 20 × 0.62 = 12.4 → +12
Maria’s new rating is 1850 + 12 = 1862.
Another way to read it: across her 5 rated games Maria was expected to score 2.88 points and actually scored 3.5. She beat expectations by 0.62 points, and each point above expectation is worth K = 20 rating points.
How unrated players get their first rating
Now take Player C, who lost to Maria in round 3. Say this is their first FIDE-rated tournament, and these are their 7 games:
| Opponent rating | Result |
|---|---|
| 1850 (Maria) | Loss |
| 1650 | Win |
| 1720 | Draw |
| 1580 | Win |
| unrated | Win |
| 1500 | Win |
| 1600 | Loss |
For an unrated player, FIDE uses a different method:
- Only games against rated opponents count. The win against the other unrated player is ignored. That leaves 6 games and 3.5 points.
- Add two hypothetical opponents rated 1800, and score them as draws. This keeps a first rating from being too extreme on few games. Now we have 8 games and 3.5 + 1 = 4.5 points.
- Average the opponents’ ratings (Ra), including the two 1800s:
Ra = (1850 + 1650 + 1720 + 1580 + 1500 + 1600 + 1800 + 1800) / 8 = 13500 / 8 = 1687.5 - Turn the percentage score into a rating difference (dp). 4.5 / 8 = 0.5625, which rounds to 0.56. From the conversion table in section 8.1.1, p = 0.56 gives dp = +43.
- Initial rating: Ru = Ra + dp = 1687.5 + 43 = 1730.5 → 1731, rounded to the nearest whole number.
| p | dp | p | dp | p | dp |
|---|---|---|---|---|---|
| 0.90 | +366 | 0.60 | +72 | 0.40 | −72 |
| 0.80 | +240 | 0.56 | +43 | 0.30 | −149 |
| 0.70 | +149 | 0.50 | 0 | 0.20 | −240 |
Player C’s first FIDE rating is 1731. From here, they use K = 40 until they have completed 30 rated games.
Special cases and peculiarities
The 400-point rule
A rating difference of more than 400 points is treated as exactly 400. So the favourite never “expects” more than 0.92 per game, and an upset is never worth more than about 0.92 × K.
Since 1 October 2025, the cap applies only to players rated below 2650. For players rated 2650 and above, the real difference is always used. In practice, a super-GM beating a much weaker opponent gains close to nothing, as the statistics say they should.
Games against unrated opponents don’t count for you
As in Maria’s example: if you’re rated, a game against an unrated player has no effect on your rating, win or lose. The game only counts toward the unrated player’s first rating. This is why beating an unrated player who turns out to be very strong gives you no reward, and losing to one costs you nothing.
A related rule: matches (not tournaments) in which one player is unrated are not rated at all.
When the “unrated” player gets rated mid-way
If an unrated player receives a published rating before one of their tournaments is processed, FIDE rates them in that tournament as a rated player, using their new rating. But for their opponents, they still count as unrated, so those opponents’ games against them still don’t count.
Forfeits and unplayed games
Forfeits, byes and other unplayed games are never rated, whatever the reason. The flip side: a game where both players have made at least one move is rated (barring force majeure or fair-play decisions). A game lost after 1.e4 e5 and a no-show still counts.
Zero points in your first event
If an unrated player scores 0 points in their first event, that event is simply ignored. It doesn’t count toward the 5 games needed for a first rating.
Requirements for a first rating
- At least 5 games against rated opponents. They don’t have to be in one tournament.
- Results are pooled across tournaments played within consecutive rating periods of at most 26 months.
- The resulting rating must be at least 1400. Otherwise no rating is published.
- The maximum initial rating is 2200, however well you did.
The 1400 floor
The lowest published FIDE rating is 1400. If your rating drops below 1400, you appear as unrated on the next list, and from then on you are treated like any other unrated player: you must earn a first rating again.
The K × n > 700 cap
Players with a high K who play many games in one month have their K reduced. If K × n > 700, where n is the number of games in the rating period, K becomes the largest whole number such that K × n ≤ 700.
Example: a junior with K = 40 who plays 20 rated games in one month would have K × n = 800. Their K for that period drops to 35 (35 × 20 = 700).
K = 10 is forever
Once your published rating reaches 2400, your K is 10 permanently. Even if you drop to 2350 later, you don’t go back to K = 20.
Juniors: K = 40 until 18
Players keep K = 40 until the end of the year in which they turn 18, as long as their rating is under 2300. A 17-year-old rated 2250 still moves at twice the speed of an adult at the same level.
Everything in a month is calculated together
Ratings are published monthly, on the first day of each month. All tournaments rated in the same period are calculated from the same starting rating, and their ΔR values are summed before rounding. Your rating doesn’t update between two tournaments in the same month.
Rounding happens once per rating period, on the total change, with 0.5 rounded away from zero (+12.5 becomes +13, −12.5 becomes −13).
Tournaments must end at least 3 days before the list date to be included in it. A tournament report that isn’t submitted in time for the third list after the tournament ends is not rated at all.
Time control matters
A game only counts for the standard rating if each player has at least a minimum amount of time, assuming a 60-move game:
- 120 minutes each if either player is rated 2400 or more
- 90 minutes each if either player is rated 1800 or more
- 60 minutes each if both players are rated below 1800
Faster games go to the separate rapid and blitz rating lists, which have their own regulations.
Inactivity
If you play no rated games for one year, you’re flagged as inactive. Your rating doesn’t change. You become active again on the next list after you play at least one rated game.
The March 2024 adjustment
When the current rules came into force on 1 March 2024, FIDE made a one-time adjustment to fight rating deflation at the lower end: every player rated below 2000 received 0.4 × (2000 − rating) extra points. A 1500-rated player, for example, gained 200 points. The same reform raised the rating floor from 1000 to 1400. If your rating jumped overnight in 2024, this was the reason.
Summary
- For each game against a rated opponent, find the rating difference, capped at 400 if you’re below 2650.
- Look up your expected score PD in the FIDE table.
- Compute score − PD for each game and add them up.
- Multiply by your K: 40, 20 or 10, and capped so K × games ≤ 700.
- Round to the nearest whole number, and that’s your change on the next monthly list.
Good luck in your next tournament, and may your ΔR always be positive!