Chess analysis in your browser
Load a position or import a game and get the engine's evaluation, best move and principal variation. The engine runs as WebAssembly on your own device, so analysis starts instantly and your games stay on your machine. Free, and no account needed.
Load a game
Find your games by Chess.com or Lichess username, or use a game link or a PGN.
What you get
- Evaluation as you move
- Every position is assessed as you play through it, with the score, the depth reached and the search progress shown beside the board.
- The best line, shown
- The principal variation is the engine's expected continuation and the reason for its score. You can play it out on the board or step through it move by move.
- Multiple engine lines
- Ask for two or three candidate lines to see whether a position has a single answer or several acceptable ones.
- Depth you control
- Trade waiting time for a deeper search. The engine runs on your hardware, so how far to look is your decision rather than a fixed setting.
- A review of the whole game
- Grade every move, see which ones changed the evaluation, and read the best move you missed at the moments that mattered.
- FEN and PGN support
- Start from any position with a FEN, or import a complete game from a PGN with its headers, comments and result intact.
How analysis works here
- 01
Load
Paste a FEN to set a position, or paste a PGN to load a whole game. You can also fetch your recent games from Chess.com or Lichess by username.
- 02
Analyze
Move pieces or step through the game. The engine searches each position in a Web Worker, so the board never freezes.
- 03
Understand
Read the line, check the graph for the turning points, and save the positions worth solving again later.
Learn the vocabulary
The guides explain what the numbers mean, so the analysis teaches you something rather than just reporting a score.
How to Analyze a Chess Game
A step-by-step method for reviewing your own games: import, find the turning points, understand the mistakes, and turn each one into something to practise.
4 min read
Chess Evaluation Explained: +1.2 and M3
What the engine's evaluation number means, how it is measured, what mate scores look like, and how much confidence a given number deserves.
4 min read
Chess Engine Depth Explained
Depth is how many plies ahead the engine searched. Learn what it does and does not tell you, and how to choose a depth that fits your purpose.
4 min read
Chess Move Classifications Explained
What inaccuracy, mistake, blunder, best and brilliant actually mean, how they are derived from engine scores, and why the label depends on the analysis.
4 min read
Also useful: Chess board coordinates explained · FEN fields explained, with examples
Frequently asked questions
- Is this chess analysis free?
- Yes. The analysis board, engine analysis, FEN editor and PGN viewer are all available without an account or a payment. Because the engine runs on your own device, there is no server cost to pass on.
- Where does the engine run?
- The engine runs as WebAssembly inside a Web Worker in your browser. It uses your device's CPU, so positions are never uploaded and the interface stays responsive while the engine searches.
- How deep can I analyze?
- Depth is yours to choose. Because the engine runs on your hardware, the depth control goes up to 99 plies, though deeper searches take longer and you can stop at any point.
- Can I analyze a game I played elsewhere?
- Yes. Export the game as PGN from whichever site you played on and paste it in. The board, move list and engine all load from the PGN, and you can then step through the game or run a review across every move.
- Do I need to know chess notation?
- No, but it helps you get more from the analysis. The board accepts drag and drop or click-to-move, and the move list is written in standard algebraic notation, which is explained in the notation guides.
- What does the evaluation number mean?
- It is the engine's assessment in pawns from White's perspective. Positive means White is better, negative means Black is better, and a score beginning with M indicates a forced mate distance rather than a pawn count.