Chess accuracy calculator
Paste a game below and GameLens runs it through a real Stockfish engine in your browser, comparing every one of your moves against the best line. Your accuracy is computed with the same formula Lichess uses — based on how much each move changed your winning chances, not just centipawn loss.
You get separate scores for White and Black, average centipawn loss, and a full move-by-move breakdown showing exactly where the game slipped.
Runs entirely in your browser — the game never leaves your device.
What counts as good accuracy?
- • 90–100 — master level, near-perfect play
- • 80–90 — strong club player
- • 70–80 — solid amateur, a few leaks per game
- • 50–70 — several decisive mistakes
- • < 50 — the engine found real gifts for your opponent
Accuracy varies by opening complexity — sharp tactical games naturally score lower than quiet ones. Judge yourself against your own recent games.