Skip to content
Chessblood

100% free · No ads · No premium tier

Free chess analysis.
No limits.

Stockfish game review with move grades, accuracy and key moments for your Chess.com, Lichess and PGN games. The engine runs in your browser, so nothing is queued, capped or sold.

Analyze a game Open the analysis board
  • Stockfish 19
  • Private by design
  • Chess.com, Lichess, PGN

We fetch your recent games from the public Chess.com API. Nothing is stored on our servers.

Your games are analysed locally. Nothing is uploaded unless you share a report.

From game to report in three steps

  1. 1

    Import a game

    Type a Chess.com or Lichess username and pick a recent game, paste a PGN, or upload a file with hundreds of games.

  2. 2

    Stockfish reviews every move

    Stockfish 19 runs inside your browser, so the analysis is private and there is no queue. A typical game takes about 15 seconds on a laptop.

  3. 3

    Read the report

    Accuracy for both sides, a grade for every move, the key moments that decided the game, and the engine's better move each time you slipped.

Everything a paid plan gives you, for nothing

Why it is free →

Transparent grading

How every move is graded

Grades are computed from the change in win probability before and after your move, using the same centipawn-to-win model Lichess published. The thresholds are fixed and documented here, so a “blunder” means the same thing in every game you review.

Brilliant and great moves need more than a low loss: a brilliant move sacrifices material the engine confirms is sound, and a great move is the only move that keeps the balance.

Read the full explanation
GradeRule
⧉BookThe position after the move appears in the ECO opening table (3,600 named positions).
→ForcedThere was only one legal move. Forced moves are never praised or punished.
!!BrilliantThe engine's top move (or within half a point of it), and along the engine's continuation the mover is still at least two pawns' worth of material down after their own next reply. Ordinary trades never qualify. The position must not already be decided, and the mover must keep at least 35% winning chances.
!GreatThe engine's top move in a position where the second-best move would have cost at least 10 percentage points of win probability: the only good move. Recaptures, captures of an equal or bigger piece and replies to check are excluded, because they are the natural move anyway.
★BestMatches the engine's first choice, or loses no more than half a percentage point of win probability.
✓ExcellentLoses less than 2 percentage points of win probability.
·GoodLoses less than 5 points.
?!InaccuracyLoses between 5 and 10 points.
?MistakeLoses between 10 and 20 points.
×Missed winThe mover had at least 85% winning chances and the move dropped them below 60% without falling below 30%. The win is gone but the game is not.
??BlunderLoses 20 points or more, or converts a winning position into a lost one.

All tools

Analyze

Review games from Chess.com, Lichess or PGN.

Tools

Engine, position and rating calculators.

Learn

Openings, puzzles and coaching.

Questions people ask

Is Chessblood really free?
Yes. Every tool on the site is free to use without an account. There is no premium tier, no daily limit on game reviews and no advertising. The engine runs on your own device, which is what makes this sustainable.
How accurate is the analysis compared with Chess.com or Lichess?
The engine is Stockfish 19, the same family of engine both sites use. The default review depth is comparable to the free Lichess analysis; the Deep preset goes further. Move grades follow a documented rule set that you can read on this page.
Do you store my games?
Not unless you ask us to. Games are fetched from the Chess.com and Lichess public APIs and analysed in your browser; reports are saved in your browser's local storage. Only when you click Share is a report uploaded so the link can be opened by someone else.
Which browsers work?
Any modern browser with WebAssembly: Chrome, Edge, Firefox and Safari on desktop and mobile. Browsers that support cross-origin isolation get the multi-threaded engine, which is roughly three times faster.
Can I analyse games from other sites or over-the-board games?
Yes. Paste or upload any PGN. Multi-game files are split automatically so you can pick the game you want.

Ready to see what the engine thinks?

Import a game from Chess.com or Lichess, or paste a PGN. The review takes under a minute and runs entirely in your browser.

Analyze a gameOpen the analysis board

100% free · No account · No ads