Elo Rating Calculator
Works out the rating change from one game.
Your new rating
—
Share sends a link that reopens these numbers. Copy details pastes the full breakdown as a list.
Rating change —
Your expected score — %
Opponent’s new rating —
The formula
E = 1 ÷ (1 + 10^((Rb − Ra) ÷ 400)) new rating = R + K × (S − E)
S is 1 for a win, 0.5 for a draw and 0 for a loss. E counts a draw as half a win.
What to watch out for
Some federations round the result or limit the rating difference they use, so a published rating can differ slightly.
Frequently Asked Questions
What does a 200-point gap mean?
The lower-rated player has an expected score of 24.0%.
How much does beating a stronger player gain?
At K = 32, a 1500 beating a 1700 gains 24.3 points.