Chess Win Probability Calculator
Calculate chess win, draw, and loss probabilities from Elo rating difference.
Enter both ratings to see expected outcomes based on the Elo system.
Win Probability
Elo Expected Score Formula
Expected Score = 1 / (1 + 10^((Opponent Rating - Your Rating) / 400))
This formula, developed by physicist Arpad Elo, gives your expected score (where 1 = win, 0.5 = draw, 0 = loss).
Rating difference examples:
- 0 points difference: 50% win rate
- 100 points advantage: ~64% expected score
- 200 points advantage: ~76% expected score
- 400 points advantage: ~91% expected score
Draws are most common at small rating differences and rare at large gaps.