Why we built it
Most players improve fastest by studying their own games, but a full engine review usually sits behind a subscription, and a wall of evaluation numbers doesn’t explain much. We wanted a tool that would point at the moment a game turned, say why in plain English, and make sure the lesson sticks.
How it works
- Review. Import your games from Chess.com or Lichess, or upload a PGN. The analyzer grades every move and explains each mistake.
- Spot patterns. Mistake DNA looks across your games to find the openings, phases and mistake types that cost you the most points.
- Practice. Every blunder becomes a puzzle in your practice deck, which brings it back on a spaced-repetition schedule until you find the right move.
- Learn. New to the game? The Learn course teaches every rule on an interactive board.
What we believe
- Free for everyone. No account, no paywall, no limit on the number of games.
- Private by design. The Stockfish engine runs on your device, so your games never leave your browser. Read the privacy policy.
- Plain English. A move grade is only useful if you understand it.
- Built on open source. Analysis is powered by Stockfish.js, with chess.js and cm-chessboard. We are grateful to everyone who maintains them.
Chess Blundr is an independent project and is not affiliated with Chess.com or Lichess. Have an idea, found a bug, or just want to say hello? Get in touch.