Free Chess Analysis with Stockfish

ChessAlfa is a free online chess analysis tool that reviews your games with the Stockfish engine — import from Chess.com, Lichess, or a PGN and get instant accuracy scores, move classifications, and blunder detection in your browser. It’s completely free and unlimited — no login, no signup, and no daily limit.

How it works

  1. Enter your Chess.com or Lichess username — or paste a PGN.
  2. Pick the game you want to review.
  3. Get an instant report with accuracy, move classifications, and blunder detection, powered by Stockfish 18 (Lite).

What your game report shows

Unlimited and free, in your browser

Chess.com limits free accounts to one game review per day. ChessAlfa has no daily cap and no subscription — analyze as many games as you like. Everything runs locally with WebAssembly, so your positions are never uploaded to a server.

Frequently asked questions

Is ChessAlfa free to use?

Yes. ChessAlfa is completely free with unlimited game analysis. There is no login, no signup, no daily limit, and no premium paywall — unlike Chess.com, which restricts free users to one game review per day.

What chess engine does ChessAlfa use?

ChessAlfa runs Stockfish 18, the strongest open-source chess engine, directly in your browser via WebAssembly. Because analysis happens client-side, your games are never uploaded to a server.

Can I analyze my Chess.com and Lichess games?

Yes. Enter your Chess.com or Lichess username to load your recent games, then pick one to review. You can also paste any PGN to analyze a game or position from another source.

What does the game report include?

Each report shows per-player accuracy, an evaluation graph, and every move classified as Brilliant, Great, Best, Excellent, Good, Book, Inaccuracy, Mistake, Miss, or Blunder. It detects the opening, highlights the engine’s best move, and lets you explore alternative lines and variations.

Do I need to create an account?

No. ChessAlfa works instantly with no account. Just open the site, load a game, and analyze.

How is ChessAlfa different from Chess.com Game Review?

ChessAlfa gives you unlimited free game reviews with no daily cap and no subscription, using the same move-classification system (Brilliant, Best, Blunder, etc.) and accuracy scoring. Chess.com limits free accounts to a single review per day.

What do the move classifications mean?

Brilliant (!!) marks a sound piece sacrifice; Great (!) is the only good move in a critical position; Best matches the engine’s top choice; Excellent and Good are near-best moves; Book is opening theory; Inaccuracy (?!), Mistake (?), Miss, and Blunder (??) mark increasing losses of winning chances, measured by win-probability drop.

Is my game data private?

Yes. Stockfish runs entirely in your browser, so positions and games are analyzed locally and never sent to a server.

How accurate is the analysis and can I change the depth?

ChessAlfa uses Stockfish 18, the same engine family used by titled players and analysis platforms. You can raise the search depth in Settings for deeper, more accurate evaluations, or lower it for faster reports.