Free tool
FIDE rating calculator for chess
How it works
Enter your current rating, each opponent’s rating, your results, and the FIDE K-factor that applies to you. The calculator estimates your expected score and rating change with the Elo formula. Your federation’s published rating remains the official result.
FIDE uses K = 40 for new and junior players, K = 20 up to 2400, K = 10 above it.
Expected score
0.43 / 1
43% chance equivalent against 1450
Actual score
1 / 1
New rating
1423
+22.9 points at K = 40
Calculations use the standard Elo expected-score formula. Federations and platforms apply their own rounding, rating floors, and K rules, so treat the output as a close estimate, not an official figure.
The method behind the numbers
New rating = R + K x (S - E), where E = 1 / (1 + 10^((Ropp - R) / 400))
The Elo system models every game as a probability. A 200-point rating gap gives the stronger player an expected score around 0.76, a 400-point gap around 0.91. Beating a much lower-rated opponent therefore earns almost nothing, while upsetting a higher-rated one moves your rating sharply.
The K-factor decides how fast ratings move. FIDE applies K = 40 to new players and to juniors under 18 below 2300, K = 20 once a player has an established rating below 2400, and K = 10 after a player has been 2400 or higher. Online platforms use their own systems and parameters, which is one reason online and FIDE numbers differ.
For a multi-game event, expected scores are summed per game against each opponent and the change is applied to the total, which is exactly what this calculator does when you add games.
Frequently asked questions
How many points do I gain for beating a higher-rated player?
It depends on the gap and your K-factor. Against an opponent 200 points above you at K = 40, your expected score is about 0.24, so a win earns roughly 30 points. At K = 20 the same win earns about 15. The calculator shows the exact value for your numbers.
Why did my rating drop after a draw?
A draw against a lower-rated opponent scores 0.5 when your expected score was higher than 0.5, so the difference is negative. Elo treats a draw with a weaker player as underperformance, which is why strong players lose points drawing down.
Is this the same number FIDE will publish?
It uses the same expected-score formula, but official calculations add details such as rating floors, the 400-point difference rule, and rounding conventions, and your federation applies them to rated events only. Treat this as a close estimate and check ratings.fide.com for official figures.
Why are my Lichess and Chess.com ratings so different from FIDE?
Different player pools and different rating systems. Lichess and Chess.com use Glicko-family systems with their own starting points and deviations, and the average strength of each pool differs, so the same player carries three different numbers. Compare trends, not absolute values.
What is a K-factor and why does it matter?
The K-factor sets how many rating points are at stake in a single game: the point change is K times the difference between your actual score and your expected score. A bigger K means bigger swings in both directions, win or lose. FIDE uses K = 40 for new players and for juniors under 18 rated below 2300, K = 20 once a rating is established below 2400, and K = 10 after a player reaches 2400. The same result against the same opponent moves a rating four times as far at K = 40 as it does at K = 10, so switching the K selector shows a coach the realistic range before a student’s bracket is confirmed.
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