USCF Rating Calculator
Enter your US Chess rating, how many rated games it is based on, and your results. You get an estimate of your new rating, with K, bonus points and the special formula for new players.
Standard formula. Effective games 16.57, K 38.89. Score 2.5 against an expected 1.532, so K × (S − E) = +37.63, plus a bonus of 17.63 for clearing 20.00.
Established: based on 44 games after this event.
| # | Opponent | Result | Expected | Change |
|---|---|---|---|---|
| 1 | 1450 | Win | 0.571 | +16.67 |
| 2 | 1620 | Loss | 0.334 | -12.99 |
| 3 | 1580 | Win | 0.387 | +23.85 |
| 4 | 1700 | Draw | 0.240 | +10.10 |
An estimate: US Chess rates the event a second time with your opponents' new ratings, and may hold you at a rating floor.
Worked example
A player rated 1500, with 40 rated games behind that rating, plays a 4-round Swiss against 4 different opponents. These are the games the calculator above opens with.
- Effective games: 50 / √(0.662 + 0.00000739 × (2569 − 1500)²) = 16.57. That is smaller than 40, so N' = 16.57.
- K = 800 / (16.57 + 4) = 38.89.
- Expected score, game by game, from the table below: E = 1.532. The actual score is S = 2.5.
- K × (S − E) = 38.89 × 0.968 = 37.63.
- Bonus: 4 games against different opponents, so the line is 10 × √4 = 20.00. The result clears it by 17.63, and that amount is added again.
- New rating: 1500 + 37.63 + 17.63 ≈ 1555.3, published as 1555.
| Opponent | Result | Expected | K × (S − E) |
|---|---|---|---|
| 1450 | Win | 0.571 | +16.67 |
| 1620 | Loss | 0.334 | -12.99 |
| 1580 | Win | 0.387 | +23.85 |
| 1700 | Draw | 0.240 | +10.10 |
How US Chess calculates a rating
US Chess rates each event as a whole. For a player who already has a rating R based on N games, playing m games in the event, the steps are these.
S is your score in the event. The last term is the bonus, and it applies only with at least 3 games and no opponent met more than twice (more than once in a 3-game event). Its multiplier has been 10 since 1 January 2025. For a Regular rating above 2200 in a dual-rated event (main time in minutes plus delay or increment in seconds from 30 to 65), K is 800 × (6.5 − 0.0025R) / (N' + m) up to 2500 and 200 / (N' + m) from 2500.
The special formula, for 8 games or fewer
If your rating is based on 8 games or fewer, or every earlier game was a win, or every one was a loss, US Chess uses the special formula instead. It uses a straight-line expectancy: 0.5 against an equal rating, moving 1/800 per point and stopping at 0 or 1 when the gap reaches 400. Your new rating is the rating at which your expected score over the event, plus N' games against your old rating, equals your actual score plus N'/2. When every earlier game was a win, the old rating counts 400 lower and the earlier games count as wins; when every one was a loss, it counts 400 higher and they count as losses. The special formula never returns more than 2700.
Provisional and established
A rating based on 25 games or fewer is provisional, and established after that. No rating goes below 100.
What this estimate leaves out
- The second pass. US Chess rates an event twice and the second time uses each opponent's rating from the first pass, which you cannot know in advance. This calculator uses their ratings before the event.
- Personal rating floors. Only the floor of 100 is applied. US Chess also keeps a floor 200 points under your highest established rating (rounded down to a hundred, from 1200 to 2100) and floors set by large cash prizes. For over-the-board ratings there is also a personal floor between 100 and 150 that grows with wins, draws and events of three or more games, and Original Life Masters keep a 2200 floor in over-the-board Regular.
- Unrated players. A first rating starts from your other US Chess ratings, a FIDE or Canadian rating, or your age, before the special formula runs. This calculator needs a rating to start from.
- Individual matches and FIDE events abroad. Matches have their own limits (no bonus, at most 50 points per match), and results in FIDE events abroad are added to a US Chess rating separately.
- Decimals. US Chess keeps ratings with decimals and publishes them rounded, so starting from the rounded figure can move the result by a point.
How close it gets: on 23 October 2026 we replayed 111 published results from 3 US Chess events. Running both passes reproduced every one of them to within 0.02 points; this one-pass estimate came within 2 points of the published rating for 97 of the 111 and was at most 9 points off. Players held at a personal floor were left out.
Source: The US Chess Rating system by Mark E. Glickman and Thomas Doan, revision of April 6, 2026, listed as the current specification on the US Chess Ratings Committee chair's page. Read on 23 October 2026.
Playing FIDE-rated events too? The FIDE rating calculator follows FIDE's own rules, and the Elo calculator shows the win probability and rating change for a single game.
USCF rating calculator FAQ
How accurate is this US Chess rating estimate?
It uses the published formulas. The main difference: US Chess rates every event twice, and the second pass uses your opponents' ratings after the event. You only know their ratings before it, so that is what this uses. Personal rating floors are not applied either. We checked it against 111 published results from three US Chess events (on 23 October 2026): it came within 2 points for 97 of them, and was at most 9 points off.
How is the US Chess K factor calculated?
K = 800 / (N' + m), where m is the number of games you played in the event and N' is your effective number of games: the number of rated games your rating is based on, or 50 / √(0.662 + 0.00000739 × (2569 − R)²) if that is smaller, where R is your rating. Above 2355 that second number is simply 50. Players above 2200 get a smaller K for their Regular rating in a dual-rated event.
How do bonus points work?
If K × (score − expected score) is bigger than 10 × √m, with m counted as at least 4, the amount above that line is added a second time. You need at least 3 games, and you must not have played anyone more than twice (or more than once in a 3-game event). The line has been 10 × √m since 1 January 2025.
What is a provisional US Chess rating?
A rating based on 25 games or fewer. If your rating is based on 8 games or fewer, or every earlier game was a win or every earlier game was a loss, US Chess uses a special formula: it finds the rating at which your expected score equals your actual score. In the usual case your earlier games count too, as your effective number of games against your old rating, scored at 50%. Above 8 games the standard formula applies, even while the rating is still provisional.
Is a USCF rating the same as a US Chess rating?
Yes. US Chess is the name the United States Chess Federation (USCF) uses today, so a USCF rating and a US Chess rating are the same thing. Regular, Quick and Blitz ratings are kept separately, over the board and online, and the same formulas apply to each.
How does a FIDE rating compare with a US Chess rating?
They are separate ratings with different formulas. When a player without a US Chess rating has a FIDE rating, US Chess converts it to help set a starting rating: 20 + 1.02 × FIDE above 2000, and −1073 + 1.5667 × FIDE at 2000 or below (since 1 March 2024). US Chess uses this conversion for two things: a new player's starting rating, and opponents' ratings when it updates a US player's rating from FIDE events abroad (youth events such as the World Youth Championships use a conversion of their own).