Understanding Chess Accuracy Ratings: What the Numbers Mean

What is chess accuracy?

Chess accuracy is a number from 0 to 100%. The less your moves lose compared with the engine’s best moves, the higher it is. A game gets 100% when none of your moves made the engine’s evaluation worse.

How is accuracy calculated?

1. The engine evaluates the positions. For every move, Stockfish finds the best continuation and its evaluation, then the evaluation after the move you played.
2. The loss is measured in centipawns. A centipawn is one hundredth of a pawn. The difference between the two evaluations is what the move lost.
3. The loss is converted into win probability. The same centipawns are worth different amounts. In an equal position, three pawns cost about 25 percentage points of win probability. When you are already a queen down, they cost about 2. From here on the loss is counted in percentage points.
4. The loss becomes the move’s accuracy. A move that loses nothing gets 100%, and the more a move loses, the lower its accuracy. The game’s accuracy is the average over your moves, with the moves labeled Book left out.

An example. The best move kept the evaluation at +1.50, an advantage of a pawn and a half, and you played a move evaluated at +0.80. You lost 70 centipawns. By the formula, +1.50 and +0.80 are about 63% and 57% win probability. The move lost 6 percentage points, and its accuracy is about 76%.

The Lichess formula

chess.rodeo scores each move with the same formulas as Lichess:

Win% = 50 + 50 * (2 / (1 + exp(-0.00368208 * centipawns)) - 1)
Accuracy = 103.1668 * exp(-0.04354 * (Win% lost per move)) - 3.1669

The first line turns an evaluation in centipawns into win probability: +1.00 is about 59%. The second turns the win probability a move lost into that move’s accuracy, from 0 to 100%.

What is a good accuracy?

By rating

We measured the averages from our own analyzes. The table covers rapid games from Chess.com that chess.rodeo analyzed: our accuracy, and next to it what Chess.com itself reported for those very same games.

Measured on 11 September 2026 across 9,819 player-sides; more in the accuracy calculator. The two sites use different scales, so compare your accuracy within one of them.

By time control

Accuracy in bullet and blitz is lower than in rapid and classical: there is less time to calculate, and even strong players make more mistakes. The table above is measured on rapid games, and its numbers do not apply to other time controls.

Move classification

Accuracy is a number for the whole game, and a label belongs to one move. The label is computed from the same thing as accuracy: how many percentage points (pp) of win probability the move lost compared with the engine’s best move.

Four more labels follow their own rules:

• Book is a known opening move early in the game.
• Brilliant (!!) is a sacrifice that loses no more than 2 pp.
• Great (!) is the only strong move in the position, one that carries out a tactic or changes the result of the game.
• Miss is a move that passes up a tactic: an undefended piece, a fork, a pin.

Why accuracy varies between platforms

Chess.com, Lichess and chess.rodeo show different accuracy for the same game, and the difference can be large: in the table above, the Chess.com and chess.rodeo averages for players under 800 are 17 points apart. There are four reasons.

• Search depth. The deeper the engine searches, the more reliably it identifies the best move. A move that is best at depth 15 can give way to another at depth 25.
• Number of lines. An engine can search one best line or several at once. With several lines the search is split between them, and in the same time the engine does not get as deep.
• The formula. Chess.com has its own scale, CAPS. Lichess and chess.rodeo score a move with the same formulas, but they put the game’s accuracy together differently. chess.rodeo takes the plain average of the move accuracies. Lichess combines a harmonic mean with an average weighted by how much the evaluation was swinging around each move. Lichess also evaluates the positions on its own, so your percentage here can differ from the one Lichess shows.
• Which moves count. chess.rodeo leaves out the moves labeled Book. Another site may have a rule of its own.

Common misconceptions

“100% accuracy is perfect play”

100% means that none of your moves made the engine’s evaluation worse. The evaluation itself depends on depth: the engine calls best the move it found within its search, and a deeper analysis may pick a different one.

“Higher accuracy always means better play”

You can lose a game with 95% accuracy. A queen blunder in an equal position gives you one move at about 10%. If the other 39 moves were played at 97%, the average comes to about 95%. Besides, once the queen is gone the position is lost, and further mistakes take away almost no winning chances. A game at 85% in which the position stayed sharp to the end, and every move had to be calculated, may have been the better-played one.

“My accuracy should match my rating”

Accuracy also depends on what kind of game it was. Where the moves are forced, as in a long series of exchanges, matching the engine is easy. In a sharp position one inaccuracy costs more than in a quiet endgame. That is why the rating table gives averages over many games, and a single game can come out above or below them.

How to improve your accuracy

1. Spend your time where a big mistake is possible. A move labeled Blunder gets under 32% accuracy, and one labeled Inaccuracy gets between 64% and 80%. In longer time controls, think longer in positions with captures and threats.
2. Before each move, look at the checks, captures and threats, yours and your opponent’s. Many blunders are a reply from the opponent that you did not look at.
3. Look for what repeats in your analyzes. Analyze several games in a row on chess.rodeo and see where the blunders and misses fall. If they come in time trouble or on the same motif, a fork for example, you know what to train.
4. Learn the basic endgames. In an endgame one wrong move can turn a win into a draw, and the analysis will label it a Blunder. In the basic endings the right moves are known in advance.

Check your accuracy: paste a username, a game link or a PGN, and once the game is analyzed you will see accuracy for both sides.