Free tool
Chess accuracy calculator
Type in evaluations, see the accuracy they work out to.
Both numbers are from the side that moved, in pawns: +1 means a pawn better for them.
Accuracy of this move
53.8%
- Chance to win before
- 52.8%
- Chance to win after
- 39.1%
- Given away
- 13.6 pts
What it does
- One move: an evaluation before and after.
- A whole game: a list of evaluations, an accuracy for each side.
- The Lichess formulas, the same ones the game review uses.
Questions
Which formula is this?
The Lichess one. Each evaluation becomes a chance of winning, the chance a move gave away becomes a move accuracy, and a game's accuracy averages those, giving more weight to moves played when the position was swinging. It is not chess.com's formula, so the numbers will not match theirs.
Where do I get the evaluations?
From any engine or analysis board that shows an evaluation per move, or from a game review. The numbers are in pawns, from White's side, and run from the starting position through every move.
Why is a small slip worth so little?
Because accuracy is measured in chance of winning, not in pawns. Giving up half a pawn in an even position barely moves the odds; the same half pawn when you are already far ahead moves them even less.
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