Free tool
Chess game analyzer
Analyze a single game move by move with Stockfish, or point it at your username and analyze every game you have ever played at once. One game tells you what went wrong on Tuesday; your whole history tells you what to actually work on. Free, in your browser, no account.
Try the board first
This is the real analysis board with Stockfish running in your browser - find the move that was missed in an actual game.
Reading the evaluation graph
When you analyze a single game, the clearest signal is the evaluation line running under the board. It stays roughly flat while the game is balanced, then jumps the instant someone plays a move that changes the result. Your job is not to read every wobble - it is to find the one or two big steps and understand them.
Say the line sits near 0.0 until move 23, then drops to -3.1 and never recovers. That step is your blunder, and the board shows both what you played and the move the engine wanted instead. Nine times out of ten the lesson is not the engine’s exact refutation - it is the reason you missed it: a hanging piece you stopped watching, a tactic you did not calculate, a plan you never had. That reason is what carries over to your next game, which is why single-game review matters even after the result is decided.
What the analysis surfaces
A single-game engine board answers “what was best here?” A history analyzer answers “what do I keep getting wrong?” Audit Chess does both:
Every mistake, labelled
Inaccuracies, mistakes and blunders flagged by the size of the win-probability swing, not a raw pawn count - so the moves that actually changed the game stand out.
Game review →Openings ranked by result
Across your history, every opening you reach becomes a tree ranked by your real win/draw/loss record, so the lines quietly costing you points are obvious.
Opening tree →The wins you threw away
Games where you had a clearly winning position and lost anyway, bucketed by whether it slipped in the opening, middlegame or endgame.
Blown wins →Puzzles from your blunders
Each real blunder becomes a Stockfish-verified puzzle that drops you back into the exact position you got wrong, so analysis turns into practice.
Blunder puzzles →How it compares
Every tool here runs Stockfish, so the difference is scope, not engine strength. Audit Chess covers your whole history at once, and still gives any single game a full move-by-move review.
| Audit Chess | Chess.com | Lichess | Stockfish | |
|---|---|---|---|---|
| Primary scope | One game and your whole history | One game (Game Review) | One game / position | One position |
| Move-by-move game review | Yes — free, unlimited | Yes — full version paid | Yes — free | Engine lines only |
| Plain-English move explanations | Yes — engine-checked | Yes (Game Review coach) | No | No |
| Cost | Free | Free tier + paid | Free | Free (open source) |
| Account needed | No | Yes | Optional | No |
| Where it runs | Your browser | Site + apps | Site + apps | Local / embedded |
| Reads your games by username | Yes — Chess.com + Lichess | Own site only | Own site only | No |
| Openings ranked by your results | Yes, with the lines costing you points | Insights (paid) | Insights + player explorer | No |
| Puzzles from your own games | Yes — a deck from all your games | Retry mistakes per game | Learn from your mistakes, per game | No |
| Opponent scouting | Yes — a prep report | Game archive only | Player explorer | No |
| Best for | Reviewing games + patterns across them | Guided single-game review | Free single-game analysis | Raw engine strength |
Attributes as of October 2026. Chess.com and Lichess also offer far more than analysis (play, lessons, tournaments); this table only compares the game-analysis angle.
One game, or all of them
Reviewing one game is the right move when you want to understand a specific loss - paste the PGN into the free analysis tool and walk the eval graph move by move, or get a labelled game review of it. But a single game is a small sample. The reason you keep losing the same way is only visible across many games, which is why the whole-history analyzer is where most of the value is.
Prefer a narrower cut? Analyze just your openings, just your blunders, or profile another player with the player analyzer.
Analysis is only useful if it changes your training
A list of engine evaluations is not a study plan. The point of analyzing your games is to decide what to drill next, so Audit Chess ends where most analyzers stop: it ranks your openings by result, surfaces the mistakes you repeat, and turns your own blunders into puzzles you can practise. For the full method, read how to analyze your chess games, or compare tools in the best free chess game analyzers.
Who is it for?
Improving players
Stop guessing what to work on. See which openings and mistakes actually cost you rating, ranked by their real impact across your games.
Competitive players
Prep with your own results and scout opponents from their public games before a rated game or match.
Coaches
Point it at any student’s Chess.com or Lichess username to see their recurring patterns in minutes instead of clicking through games one by one.
Chess enthusiasts
Understand your own chess for free - no account, no install, nothing uploaded.
What is Audit Chess?
Audit Chess is a free chess analysis platform for your Chess.com and Lichess games. It does two jobs in one place. First, it reviews any single game move by move with Stockfish: every move graded from Brilliant to Blunder, accuracy by game phase, an eval graph, and a plain-English, engine-checked explanation of each key moment. Second, it analyzes your whole history at once to find what a single game can't show: the openings that cost you points, your mistakes ranked by tactical, positional and endgame theme, the wins you throw away, missed mates, and your endgame and playstyle profile. Then it turns your own blunders into Stockfish-verified puzzles and drills. It runs in your browser, needs no account, has no review limit and never uploads your games.
In short: a complete free alternative to a paid per-game review, plus the whole-history view that tells you what to study next. See all features.
Frequently asked questions
How do I analyze a chess game?+
For a single game, paste its PGN into the free analysis tool and Audit Chess replays it move by move with Stockfish, marking every inaccuracy, mistake and blunder and drawing the evaluation graph. To analyze all your games at once, enter your Lichess or Chess.com username and it reviews your whole history and ranks where you actually lose points.
Do I need to upload a PGN file?+
No. You can paste PGN text for one game, or skip files entirely and enter a username - Audit Chess reads your public games straight from the Lichess and Chess.com APIs. Nothing is uploaded to a server either way; the engine runs in your browser.
What engine does it use, and how deep?+
It runs Stockfish compiled to WebAssembly, locally in your browser. The whole-history pass scans every move quickly so it can cover hundreds of games; single-game review and puzzle checking then run a deeper analysis on demand, position by position.
Is it really free?+
Yes - free, no account, no install. Because the analysis happens on your own device there is no server cost to pass on and nothing about your games leaves your machine.
Audit Chess is free and not affiliated with Chess.com or Lichess.