ChessAnalysis (chessanalysis.dev) is a free chess analysis site for club players. Import a game from Chess.com or Lichess, or paste a PGN, and get a full review: accuracy for both sides, every inaccuracy, mistake and blunder, and a short explanation of your biggest mistakes with the move you should have played.
How the review works
The analysis is done by Stockfish 19, the open-source chess engine, running in your own browser. Every position is analyzed at depth 12 and your key mistakes at depth 18, so a review costs us nothing and there is no daily limit. Accuracy uses the formula Lichess publishes, explained on the chess accuracy page.
Explanations of your key mistakes are built from the engine's lines and a set of rules that detect forks, pins, hanging pieces, mates and material changes. Where an AI model writes the explanation, every piece, square and move it mentions is checked against the board before it is shown; if the check fails, you see the rule-based explanation instead.
Free tools
Besides the game review, there is an analysis board, a next move calculator, a board editor, a chess clock, an Elo calculator and a guide to the chess board setup.
Independence
ChessAnalysis is not affiliated with Chess.com or Lichess. Games are read from their public APIs in your browser. Our move labels and colours are our own.
Fair play
The tools are for studying finished games and positions. Please do not use them in a game you are playing; engine help during a game breaks the rules of every chess site and tournament.
Corrections and contact
If an explanation or evaluation looks wrong, email support@chessanalysis.dev with the PGN or FEN and the move number. Confirmed errors are fixed and the position is added to our automated checks.