Elo Rating Calculator
Calculate your new Elo rating after any match.
Enter your rating, opponent's rating, result (win/draw/loss), and K-factor to see your exact rating change.
The Elo rating system, developed by physicist Arpad Elo in the 1960s, is a method for calculating the relative skill levels of players in competitive games. It is used in chess, video games, sports leagues, and many online platforms.
Expected score formula: Expected Score (A) = 1 ÷ (1 + 10^((Rating_B − Rating_A) / 400))
This gives the probability that Player A will win (1 = win, 0.5 = draw, 0 = loss).
Rating update formula: New Rating = Old Rating + K × (Actual Score − Expected Score)
Where:
- Actual Score: 1 for win, 0.5 for draw, 0 for loss
- K-factor: controls how quickly ratings change
K-factor values in chess (FIDE standard):
- K = 40 for new players (first 30 games)
- K = 20 for established players (under 2400)
- K = 10 for top players (2400+)
Worked example: Player A (rated 1500) beats Player B (rated 1700). Expected Score (A) = 1 ÷ (1 + 10^((1700−1500)/400)) = 1 ÷ (1 + 10^0.5) = 1 ÷ 4.162 = 0.240
Rating Change (A) = 20 × (1 − 0.240) = 20 × 0.760 = +15.2 points New Rating (A) = 1500 + 15 = 1515 New Rating (B) = 1700 − 15 = 1685
Rating benchmarks (chess):
- Below 1000: Beginner
- 1000–1400: Intermediate club player
- 1400–1800: Strong club player
- 1800–2200: Expert / candidate master
- 2200–2400: FIDE Master
- 2500+: Grandmaster territory
- Magnus Carlsen peak: 2882
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
SuperGlobalCalculator is independently built and maintained. See how we build and verify our calculators.