Expected Score Calculator

Understanding Expected Score in Chess

The expected score is the statistically predicted result between two rated players. It tells you what percentage of points you should score against a specific opponent over many games. This is the foundation of the entire Elo rating system.

The Math Behind Expected Score

E_A = 1 / (1 + 10^{(R_B−R_A)/400}). For a 200-point rating difference, the higher-rated player is expected to score 76%. A 400-point gap = 91% expected. At equal ratings, both players have 50% expected score.

Practical Applications

• Tournament prep: Calculate how many points you need to score against the field to gain rating.
• Opponent selection: Understand which opponents offer the best rating-gain potential.
• Team strategy: In team matches, estimate your team's expected score against opponents.
• Rating goals: Set realistic expectations for tournament performance.

Draw Probability

The expected score formula gives total expected points, not win/draw/loss probabilities separately. In practice, draws become more likely as ratings get closer. At equal ratings among strong players, the draw rate can exceed 40%, meaning win/loss probabilities are actually lower than the expected score suggests.

Frequently Asked Questions