Free Chess Game Analysis with Stockfish
Analyze your chess games for free with the full Stockfish engine, running entirely in your browser. Paste a PGN or load your recent chess.com and lichess games to get a move-by-move review — accuracy, blunders, mistakes, and the best move in every position.
There is no signup and nothing to install. Your games are evaluated locally on your own device, so the analysis is private and there are no daily limits.
Game review works for every time control — rapid, blitz, bullet or a slow classical game — and for any opening. Step through the game move by move, or jump straight to the moments that decided it to see the evaluation swing and the move you should have played instead.
What the game review gives you
Move-by-move accuracy
Every move is graded against Stockfish's best line, with an accuracy score for the whole game and a clear label for each move — brilliant, best, good, inaccuracy, mistake or blunder.
Find your blunders
The review pinpoints where the game turned, shows the evaluation swing, and gives you the move you should have played instead so you can learn from it.
chess.com & lichess games
Load your latest rapid, blitz or bullet games straight from your chess.com or lichess username, or paste any PGN to review a single game.
Accuracy and game rating
Get an overall accuracy percentage for each side and an estimated strength for the game, so you can track whether your play is improving over time.
Brilliant moves and key moments
The review highlights your best finds — brilliant and great moves — alongside the errors, so you see what you did well, not only what went wrong.
Runs in your browser
Stockfish (WebAssembly) runs on your own device. No account, no uploads, no cost — review as many games as you like, and nothing you analyze is sent to a server.
How to review your chess game
Load your game
Enter your chess.com or lichess username to pick a recent game, or paste the PGN of any game you want to review.
Run the review
Stockfish evaluates every move on your device and grades it against its best line, then scores the accuracy for both sides.
Find the turning points
Jump to the blunders and mistakes to see the evaluation swing and the stronger move you should have played instead.
Learn and replay
Step through the game move by move, explore the engine's suggestion in each position, and carry the fixes into your next game.
Frequently asked questions
Is the chess analysis really free?
Yes, and it is unlimited. Where chess.com gives free members only one game review a day, here you can review as many games as you like for nothing — no signup and no daily limit. Every feature (game review, blunder detection, accuracy and stats) is free because Stockfish runs locally in your browser.
Can I analyze my chess.com and lichess games?
Yes. Just enter your chess.com or lichess username to load your recent games and review as many of them as you want, or paste a PGN to analyze any single game — no linked account required.
Can I analyze a game from a PGN?
Yes. Paste the PGN of any game — one of yours or someone else's — and the review evaluates every move with Stockfish and grades the accuracy, with no chess.com or lichess account needed.
Which engine is used?
The analysis uses Stockfish 18, one of the strongest chess engines in the world, compiled to WebAssembly so it runs directly on your device.
What is a good accuracy score?
It depends on the level, but broadly casual games often land in the 70–85% range, strong club players are frequently above 90%, and near-perfect games approach 99%. The review shows an accuracy percentage for both sides so you can compare.
What is the difference between a mistake and a blunder?
Both measure how much a move loses versus Stockfish's best line. A blunder is a serious error that can swing the game, a mistake is smaller but still costly, and an inaccuracy is a minor slip. The review labels every move so you can see how bad each one was.
Do I need to create an account?
No. You can review games without an account. An optional account only adds cross-device sync for puzzles and streaks.