Work out how many rating points a game is worth. Enter your rating, your opponent's rating, the K-factor and the result to see the expected score, the rating change for both players and the new ratings, or list several games to rate a whole tournament.
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Enter your values to see the result.
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How to use the Elo Rating Calculator
Choose one game or several games.
Enter your rating and your opponent's rating.
Pick the K-factor your federation, site or league uses.
Select the result, or list each opponent's rating and your score on its own line for a tournament.
Read the rating change and compare all outcomes in the table.
The Elo formula
Expected score: EA = 1 ÷ (1 + 10(RB − RA) ÷ 400), and EB = 1 − EA
New rating: R′A = RA + K × (SA − EA), with S = 1 for a win, 0.5 for a draw, 0 for a loss
Example: 1500 vs 1650 with K = 20. E = 1 ÷ (1 + 10150/400) = 1 ÷ (1 + 2.371) = 0.297. A win gives +14.1, a draw +4.1 and a loss −5.9.
Expected score by rating difference
Rating difference
Higher-rated player
Lower-rated player
Points for an upset (K = 20)
0
0.500
0.500
+10.0
50
0.571
0.429
+11.4
100
0.640
0.360
+12.8
200
0.760
0.240
+15.2
300
0.849
0.151
+17.0
400
0.909
0.091
+18.2
600
0.969
0.031
+19.4
800
0.990
0.010
+19.8
FIDE also applies a 400-point cap: for rating purposes a difference of more than 400 points is counted as 400.
Frequently asked questions
How is the Elo rating change calculated?
First the expected score: E = 1 ÷ (1 + 10^((opponent − you) ÷ 400)). Then change = K × (S − E), where S is 1 for a win, 0.5 for a draw and 0 for a loss. A 1500 player who beats a 1650 player with K = 20 has E ≈ 0.297 and gains 20 × (1 − 0.297) ≈ +14.1.
What is the expected score?
It is the average score you are expected to get against that opponent, counting a draw as half a point. At equal ratings it is 0.5; a 200-point favourite is expected to score about 0.76.
What K-factor should I use?
It depends on the rating system. FIDE uses 40 for new players (and juniors under 2300), 20 for most players and 10 for players who have reached 2400. Many online and club systems use 32, sometimes falling to 16 or 24 for established players. A higher K makes ratings move faster.
Why do both players' changes not always add to zero?
With the same K-factor, one player's gain equals the other's loss. If the two players use different K-factors, for example a new player with K = 40 against an established player with K = 20, the changes differ.
How is the tournament rating change calculated?
Each game is rated against your rating before the event, and the changes are added up: K × (total score − total expected score). This matches how FIDE rates a tournament within a rating period.
What is a performance rating?
It is the rating at which your results would be exactly as expected. The calculator shows the common linear estimate: average opponent rating + 400 × (wins − losses) ÷ games. Official FIDE performance ratings use a lookup table and can differ slightly.
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