Analyse any chess position
Set the board up, or paste a FEN. Stockfish tells you the best move, how much it is worth, and the line it expects afterwards. Free, no account, nothing to install.
Analysing from a photo?
This page needs a FEN or a board you set up by hand. The app reads a position straight from a photograph of a real board or a screenshot, and keeps your saved positions between sessions.
What the answer is telling you
Three numbers come back and each is easy to misread. Here is what each one means before you act on it.
The evaluation
Measured in pawns, always from White’s side. It is not a material count: a level position with a safer king reads as an advantage. Anything under about a third of a pawn means the engine could not separate the two sides.
How to read itThe best move
The move that scores highest assuming both sides then play perfectly. That assumption is doing a lot of work: a move needing six exact follow-ups may be a worse practical choice than a quiet one rated slightly lower.
When to ignore itThe line
Not a prediction of what your opponent will do. It is the reason the evaluation is what it is, and playing it out on the board is the fastest way to see what you missed.
Why depth mattersStart from an opening
All twenty openingsEach page loads the board at the position the moves reach, so you can play your own continuation and ask the engine about the position you actually keep getting.
- ♜♝♛♚♝♞♜♟♟♟♟♟♟♟♞♟♝♟♞♟♟♟♟♟♟♟♜♞♝♛♚♜
Italian Game
e4 e5 Nf3 Nc6 Bc4
- ♜♝♛♚♝♞♜♟♟♟♟♟♟♟♞♝♟♟♞♟♟♟♟♟♟♟♜♞♝♛♚♜
Ruy Lopez
e4 e5 Nf3 Nc6 Bb5
- ♜♞♝♛♚♝♞♜♟♟♟♟♟♟♟♟♟♟♟♟♟♟♟♟♜♞♝♛♚♝♞♜
Sicilian Defence
e4 c5
- ♜♞♝♛♚♝♞♜♟♟♟♟♟♟♟♟♟♟♟♟♟♟♟♟♜♞♝♛♚♝♞♜
French Defence
e4 e6 d4 d5
- ♜♞♝♛♚♝♞♜♟♟♟♟♟♟♟♟♟♟♟♟♟♟♟♟♜♞♝♛♚♝♞♜
Caro-Kann Defence
e4 c6 d4 d5
- ♜♞♝♛♚♝♞♜♟♟♟♟♟♟♟♟♟♟♟♟♟♟♟♟♜♞♝♛♚♝♞♜
Queen's Gambit
d4 d5 c4
Latest writing
All guides
Article
Why the Engine Hates a Move You Like
You play a natural developing move and the evaluation drops half a pawn. Four things the engine sees that a club player usually does not, and how to check which one applies.
Guide
Depth, and What It Buys You
Depth 20 is not twice as good as depth 10. What a ply is, why the returns fall away sharply, and how to tell when a position has actually been resolved.
Guide
What the Evaluation Number Actually Means
An engine's score is measured in pawns, but it is not counting pawns. What the number is, what counts as an advantage, and why anything under 0.3 is noise.
The app
Play against Stockfish, and analyse from a photograph
This page analyses a position you can already describe. Chess Engine for Stockfish does the two things a web page cannot. It plays full games against you at a strength you choose, which is the difference between studying a position and being able to play it.
And it reads a position straight from a photograph of a real board or a screenshot, which is the case where typing a FEN is most annoying and most error-prone. It also keeps your saved boards and analyses with no connection.
Common questions
- Is this chess engine free?
- Yes, and there is no account. Analysis runs from your browser against a Stockfish instance, and nothing about the position is stored against you.
- How strong is the engine?
- It is Stockfish, which has been stronger than every human player for two decades. Searches from this page run to about depth 16, which settles the great majority of middlegame positions.
- Can I analyse a game rather than a position?
- Set the board to the position you want to ask about and play on from there. For a whole game, move through it and analyse the two or three moments where you felt uncertain, which is where the useful information is anyway.
- Do I need to know FEN notation?
- No. Move the pieces on the board and the FEN is produced for you. If you already have one, paste it into the box below the board.