Play moves on the board, set up pieces or paste a FEN. Stockfish 19 runs right in your browser and draws the best move as an arrow.
How to use it
- Set the position. Make moves on the board, press “Set up position”, or paste a FEN into the box. Copied a FEN or PGN? Just press Ctrl+V anywhere on the page.
- Follow the arrow. The yellow arrow is the best move. Teal and purple show the second and third choices. The bar on the left shows who is better.
- Ask the coach. “Why this move” explains the idea, and “Opponent threats” shows what the other side is planning and which pieces are loose.
- Explore lines. Click a line to play it on the board and watch how the evaluation changes.
What it can do
Stockfish 19 in your browser
One of the strongest chess engines in the world runs on your device. Positions are never uploaded and analysis starts instantly.
Up to three lines
Compare the best continuations with their scores. Search depth goes up to 24 plies.
Position editor
Set up any position, choose who moves and castling rights. Handy for puzzles and endgames.
Plain-language explanations
The coach tells you why a move works: check, fork, capture, development or sacrifice.
Frequently asked questions
How do I find the best chess move?
Set up the position on the board or paste a FEN. Stockfish immediately shows the best move as a yellow arrow and writes it on the right.
Is the calculator free?
Yes, completely free with no sign-up.
How strong is the engine?
It is Stockfish 19 in its lightweight browser build. It plays far stronger than any grandmaster.
What is a FEN?
A single line that describes piece placement, side to move and castling rights. More in our FEN guide.
Can I use it during an online game?
No. Chess.com, Lichess and other sites forbid engine help in games against people and ban accounts for it. Review your games afterwards.