📊 Elo Rating Calculator
Calculate Elo rating changes after a match
Player A
1512
+12
Win probability: 64.0%
Player B
1388
-12
Win probability: 36.0%
Step-by-step Elo formula
- 1.Rating difference: 1400 - 1500 = -100
- 2.Expected score A: 1 / (1 + 10^(-100/400)) = 0.6401
- 3.Expected score B: 1 - 0.6401 = 0.3599
- 4.Actual result: Player A wins (A=1, B=0)
- 5.Rating change A: 32 x (1 - 0.6401) = +11.5
- 6.Rating change B: 32 x (0 - 0.3599) = -11.5
- 7.New rating A: 1500 + 11.5 = 1512
- 8.New rating B: 1400 + -11.5 = 1388
About the Elo System
- • Created by Arpad Elo for chess rating in the 1960s
- • Now used in chess, Go, video games, sports, and more
- • Higher K-factor = more volatile ratings (bigger swings)
- • A 200-point difference gives ~76% win probability to the stronger player
- • Upsets (lower-rated player winning) cause bigger rating changes
Formula: New Rating = Old Rating + K x (Actual Score - Expected Score). Expected Score = 1 / (1 + 10^((Opponent - Self) / 400))
How to Use Elo Rating Calculator
- 1Enter the current ratings for both players.
- 2Select the match result (win, loss, or draw).
- 3View the new ratings and the rating points gained or lost.
About Elo Rating Calculator
Calculate new Elo ratings after a match for chess, gaming, or any competitive system. Our Elo rating calculator lets you adjust the K-factor, view expected scores, and track rating changes over time.
Frequently Asked Questions
What K-factor should I use?
FIDE uses K=40 for new players, K=20 for established players, and K=10 for top-rated players. Many online platforms use K=32 as a default.
Can I use this for games other than chess?
Yes. The Elo system works for any 1v1 competition — video games, sports, board games, and more.