Chess Rating Calculator
Estimate expected score, Elo change and your new rating — all in your browser
Hit Calculate to see your match probability
Calculate to estimate your new rating
Metrics appear after calculation
Insights appear here
A higher K-factor produces larger rating changes from the same game result.
Your plan appears after calculation
See how another opponent rating changes your expected score.
Calculate your main result first
The Elo model uses 1 ÷ (1 + 10^((opponent rating − your rating) ÷ 400)). A score near 0.50 indicates an even matchup.
Rating change is K × (actual score − expected score). A win scores 1, a draw 0.5 and a loss 0.
Use the K-factor defined by your federation or platform. Lower values make ratings more stable; higher values help ratings adjust faster for newer or developing players.
This tool provides an educational Elo estimate. Official rating changes may differ because federations and online platforms can use different K-factors, rounding rules, pools and provisional-rating systems.
