USCF Rating Calculator (US Chess Rating Estimator)

Free USCF rating calculator: estimate your new US Chess rating after a tournament, with K-factor, bonus points, provisional ratings and rating floors.

The interactive uscf rating calculator (us chess rating estimator) loads here. It runs in your browser and is free to use.

Enter your rating, the number of rated games you have played and your results, and the calculator estimates your new US Chess (USCF) Regular rating. It is an estimate: your official rating is computed by US Chess after the tournament director submits the event and it is rated. Rating floors, unrated opponents and the timing of the monthly rating supplement can make the posted number differ.

How US Chess ratings are calculated

US Chess uses its own version of the Elo system, described in "The US Chess Rating System" by Mark Glickman. Your whole tournament is rated at once, using your rating before the event.

Step 1: effective number of games. Your rating counts as if it were based on N′ games: the number of rated games you have played, but never more than N*, a value that grows with your rating (about 17 at 1500, 29 at 2000 and 50 for 2355 and above). A small N′ means your rating moves quickly.

Step 2: special or standard formula. If N′ is 8 or less, or every rated game you ever played was a win (or every one a loss), the special formula is used. It treats your old rating as N′ games scored 50% against a player of your own rating and finds the rating that makes your total score "expected", using a straight-line expectancy that stops at 400 points. When all opponents are within 400 points, that is the familiar provisional formula: (N′ × old rating + sum of opponents' ratings + 400 × (wins − losses)) ÷ (N′ + games).

Otherwise the standard formula applies: new rating = old rating + K × (score − expected score), with K = 800 ÷ (N′ + games in the event). Expected score per game is 1 / (1 + 10^(−difference/400)).

Step 3: bonus points. With 3 or more games, a big overperformance earns a bonus: K × (score − expected) − 10 × √(games, at least 4), if positive. The bonus is skipped when you played the same opponent more than twice (or twice in a 3-game event).

Worked example

You are rated 1500 with 50 rated games, so N′ = 16.6. In a four-round Swiss you beat 1600, 1550 and 1700 and draw a 1450. Your expected score is 1.60 and you scored 3.5. K = 800 ÷ 20.6 = 38.9, so the regular gain is 38.9 × 1.90 = +73.9. The bonus threshold is 10 × √4 = 20, giving a bonus of 73.9 − 20 = +53.9. Your new rating is about 1628.

Rating floors

A rating floor is the lowest your rating can drop. As we read the US Chess rating system document:

• Absolute floor: no rating goes below 100. US Chess raises this slightly (up to 150) for players with many rated wins, draws and events.
• Peak-based floor: once you have an established rating, your floor is typically your highest established rating minus 200, rounded down to a multiple of 100. A peak of 1500 gives a floor of 1300; a peak of 1748 gives 1500.
• Highest floor: peak-based floors stop at 2100. Original Life Masters keep 2200, and big cash prizes can set a special floor.

Enter your peak and the calculator shows your floor and stops the estimate there. Floors are kept separately for Regular, Quick and Blitz. Check US Chess for the exact rules that apply to you.

Unrated players and unrated opponents

Your first rating. With no rating to convert, US Chess starts from your age: 50 × age up to 26 (a 12-year-old starts at 600), and 1300 for adults or an unknown age. As we read the rules, that starting value carries no game weight, so your first rating comes from the special formula on the event alone. Example: an unrated 12-year-old beats a 1000 and a 900, draws a 1100 and loses to a 1200: (4200 + 400 × (2 − 1)) ÷ 4 = 1150.

Unrated opponents are handled in two passes. First, each unrated player gets an estimate from the special formula, with unrated opponents counted at their age-based value. Then everyone is rated, with unrated opponents counted at those estimates. Add an unrated opponent with their age and, if you know it, their event score.

How to look up your official USCF rating

1. Go to uschess.org and open the player search in the Member Services Area (MSA).
2. Search by last name (and state, if the name is common) or by your 8-digit US Chess ID, printed on your membership card or confirmation email.
3. Your page lists your current Regular, Quick and Blitz ratings, your rating history and every rated event.
4. Open an event to see its crosstable with each opponent's rating before and after.

New events usually appear within days of the director submitting them. Many tournaments pair with the monthly rating supplement, so the rating used at your next event can be older than your latest one. Read the event's announcement.

Limits of this estimate

The official first pass uses each unrated player's actual opponents, and special floors are not modelled. The age rule and the zero game weight are our reading of the US Chess documentation. Compare with the FIDE rating calculator, which uses different rules.