Analyse your chess games, move by move
Find out exactly where the game turned - not just that you lost, but which move lost it and what the alternative was.
Try it on a sample game → Loads the Opera Game so you can run a report without importing anything first.
How to analyse a chess game
Three ways to get a game onto the board:
- Paste a PGN. Copy the game text from anywhere and paste it in.
- Import from Lichess or Chess.com. Enter a username and pick from the recent games.
- Play it out. Enter the moves on the board directly, or build a mid-game position in the board editor - useful for over-the-board games from a scoresheet.
What the report tells you
Every move is compared against the engine's best line, and the ones that lose real evaluation are marked as inaccuracies, mistakes or blunders - for both players, so you can see the chances your opponent gave you as well as the ones you gave away.
For each marked move you get the move you played, the move the engine wanted, and the evaluation swing between them. Clicking any of them puts you on that position with the full board tools available, so you can explore why rather than just accept the verdict.
The most useful habit in game review is not reading the blunder list - it is stopping at each marked move before looking at the answer and trying to find the better move yourself. The "guess the move" mode on the analysis board does exactly this.
What to look for in your own games
- When the mistakes happen. Consistently on move 15-25 means a middlegame planning problem; consistently after move 35 means time trouble or endgame technique.
- What kind they are. Hanging a piece is a checking problem; slowly getting worse is a planning problem. They need different practice.
- Whether the opening mattered. Most club players blame the opening for losses that started twenty moves later.
Keep going
Analysis board
Explore any position with live engine evaluation and best-move arrows.
PGN viewer
Just want to read a game? Paste the PGN and step through it.
Tactics puzzles
Turn the mistakes you keep making into targeted training.
Frequently asked questions
How do I analyse my chess games for free?
Import the game from Lichess or Chess.com, or paste its PGN, and run the game report. Chess Compass analyses it with Stockfish in your browser and marks every inaccuracy, mistake and blunder for both sides at no cost.
Can I import games from Chess.com and Lichess?
Yes. Enter your username and pick the game from your recent history - no password or account linking needed.
What counts as a blunder?
A move that drops a large amount of evaluation compared with the best available move - typically enough to change the result of the game with correct play. Inaccuracies and mistakes are the same idea with smaller thresholds.
Is the analysis as good as a paid site?
It uses Stockfish, the same engine behind most commercial analysis. The depth is limited by your device rather than by a subscription tier, and on a modern browser that is far deeper than any human opponent you will face.