ChessGrader / Free chess game review
Free chess game review. Unlimited. No signup.
Type your chess.com or lichess username. ChessGrader fetches your games and runs a full Stockfish review in your browser — every move graded, accuracy scored, blunders explained. As many games as you want.
What you get
The same style of report you know from Chess.com's Game Review, without the meter running:
- Every move graded — Brilliant, Great, Best, Excellent, Good, Book, Inaccuracy, Miss, Mistake, Blunder. The exact thresholds are public.
- Accuracy score — computed with the documented Lichess method, so you can actually compare it to benchmarks.
- Estimated game rating — a rough strength read from your centipawn loss. Treat it as a vibe, not a verdict.
- Eval bar and graph — see exactly where the game turned.
- Mistake drills — replay your errors until you'd find the right move at the board.
How it works
ChessGrader runs Stockfish 17.1 (NNUE) as WebAssembly, directly in your browser. Every position gets a fixed budget of 100,000 nodes, so a phone and a gaming PC produce the same grades. Then the moments that matter — potential blunders, brilliancies, big swings — are re-searched at 600,000 nodes with the engine's two best lines. Brilliant and Great labels are only awarded after that deeper check.
Because the analysis runs locally, there's no server, no queue, and no account. Your games go from the chess.com or lichess public API straight to your browser. We never see them.
Every formula — win probability, accuracy, grade thresholds, mate handling — is documented on the methodology page. If you think a grade is wrong, you can check the math.
ChessGrader vs Chess.com Game Review
Chess.com's Game Review is good. It's also capped: one free review per day, and a paid membership after that. Here's the honest comparison:
| ChessGrader | Chess.com Game Review (free) | |
|---|---|---|
| Reviews per day | Unlimited | 1 |
| Account required | No | Yes |
| Move grades | All games, documented thresholds | Blunders/mistakes need a paid plan |
| Engine | Stockfish 17.1, runs in your browser | Stockfish, runs on their servers |
| Lichess + PGN import | Yes | No |
| Coach commentary | Plain-language move explanations | Character-based coach (limited free) |
| Methodology public | Yes, fully | No, proprietary |
What we won't claim: pixel-identical numbers. Chess.com's exact formulas are proprietary, so grades can differ by a step and accuracy by a couple of points. Same engine family, same ideas, honest math.
The catch
There isn't one, but here's what to know. Analysis speed depends on your device — a modern phone takes about a minute per game. Grading is an approximation of ideas like "brilliant" that no two sites define identically. And ChessGrader only does standard chess for now: no variants, no Chess960.
Frequently asked questions
Is ChessGrader really free and unlimited?
Yes. There is no account, no daily limit, and no paid tier. Analysis runs in your browser with Stockfish 17.1 compiled to WebAssembly, so serving another game review costs us nothing — which is why we can leave it free.
Do I need a chess.com or lichess account?
You need games somewhere. ChessGrader fetches games from the chess.com and lichess public APIs by username, and you can also paste any PGN directly — from a tournament, an OTB game you transcribed, or another site.
Is it safe to type my chess.com username?
Yes. ChessGrader only reads the public game archive that chess.com already exposes for every account. There is no login, no password, and no OAuth — we could not touch your account if we wanted to.
How accurate is the analysis compared to Chess.com?
Grades typically match within one step and accuracy within a couple of points. Both tools use Stockfish; the differences come from search depth and labeling formulas. Chess.com's formulas are proprietary; ChessGrader's are published on the methodology page.
What engine does ChessGrader use?
Stockfish 17.1 with the lite NNUE network, running as WebAssembly in your browser. Every move gets a fixed 100,000-node search, and critical moments are verified at 600,000 nodes with the top two engine lines.
Where do my games go?
Nowhere. The analysis runs entirely on your device. Reports are cached in your browser storage so you can revisit them, and nothing is uploaded to a server.
Does ChessGrader work on mobile?
Yes. The engine is a single-threaded WebAssembly build chosen specifically so it runs on iOS Safari and Android browsers, with the same fixed node budget — and therefore the same grades — as on desktop.