Chess engine online
Stockfish 16.1 ยท runs in your browser
Play a move by typing it, like e4, Nf3 or e7e8q, then press Enter.
Engine
- +0.3e4 c5 Nf3 e6 Nc3 Nc6 d4 cxd4
- +0.2d4 Nf6 Bf4 d5 e3 e6 c3 Bd6
- +0.2Nf3 d5 d4 Nf6 Bf4 Bf5 e3 e6
Starting position, Stockfish 16.1 at depth 16, captured Oct 16, 2026. Press the button to run it live on your device.
What this chess engine does
It searches the position on the board and ranks the best moves, with a score and the line behind each one.
- Stockfish 16.1 runs in your browser, no download
- 1, 3 or 5 lines at depth 12, 16 or 20, and a label for every move you play
- Free, no account: play moves, or paste a FEN or PGN
How to use Stockfish
Press Start engine, then play moves or paste a FEN or PGN, and Stockfish ranks the best moves for the position on the board.
- 1
Put a position on the board
Drag or tap pieces from the starting position, or paste a FEN or the moves of a game and press Load.
- 2
Start the engine
Press Start engine. The lines update as the search goes deeper, and arrows on the board show each line's first move.
- 3
Read the lines
Each line starts with its score, then the moves Stockfish expects. Hover a line to highlight its first move on the board.
Search depth and number of lines
Depth is how many moves ahead the engine searches, and lines are the separate best moves it ranks side by side.
- Depth 12
- Stops after 4 seconds at most.
- A quick check of a position.
- Depth 16
- Stops after 8 seconds at most. The page opens on this setting.
- Studying a position before you move.
- Depth 20
- Stops after 12 seconds at most.
- The deepest search offered here, for the position you care about most.
- 1 line
- Shows only the best move.
- You want one answer.
- 3 or 5 lines
- Ranks the next-best moves too, each with its own score.
- Comparing candidate moves. More lines slow each search.
How does Stockfish work?
Stockfish searches a tree of moves and replies, then scores the positions at the end of each branch with a neural network.
Its search skips branches that cannot beat a move it has already found, which lets it look much deeper along the lines that matter. The neural network, called NNUE, is small enough to run on an ordinary processor.
This page loads the lite single-thread WebAssembly build of Stockfish 16.1, so it runs inside your browser tab and the positions you load are analyzed there. The engine downloads the first time you touch the page.
Frequently asked questions
What is Stockfish?
Stockfish is a free, open-source chess engine that searches positions and scores moves. Tord Romstad, Marco Costalba and Joona Kiiski released it in 2008, and a community of volunteers has developed it since.
Is Stockfish open-source?
Yes. Stockfish is free software under the GNU General Public License v3, and its source code is on GitHub.
Who made Stockfish?
Tord Romstad, Marco Costalba and Joona Kiiski released it in 2008, building on the open-source engine Glaurung. A community of volunteers develops it now and tests every change in a shared testing network called Fishtest.
What Elo is Stockfish?
On the CCRL 40/15 list of 16 October 2026, Stockfish 16.1 (64-bit) rates 3620, and its 4-CPU build rates 3638. Those are desktop builds. The lite WebAssembly build this page runs is not on the list, so it has no listed rating. CCRL's scale comes from games between engines and does not match FIDE or chess.com ratings.
Can Magnus Carlsen beat Stockfish?
Not realistically. Magnus Carlsen's peak FIDE rating is 2882, reached in May 2014. The CCRL 40/15 list of 16 October 2026 rates Stockfish 16.1 (64-bit, desktop build) at 3620, on a different scale built from games between engines, so the two numbers cannot be subtracted.
Carlsen's rating historyCCRL 40/15 rating list (all versions)
Is Stockfish the best chess engine?
Stockfish is one of the leading chess engines. Rating lists such as CCRL 40/15 rank engines under stated test conditions, so compare any ranking by version, hardware and time control.
What is a chess engine?
A chess engine is a program that evaluates positions and chooses moves. It has no board of its own, so this page connects Stockfish to a board where you can see its lines and arrows.
Analysis runs on Stockfish 16.1 in your browser, compiled to WebAssembly by stockfish.js. Stockfish is free software under the GNU General Public License v3; its source code is on GitHub.