Paste a position and get the best move. This free tool runs Stockfish in your browser — no signup, no upload, no limits — and shows the engine's top move, the evaluation, and its three best lines. Paste a FEN from lichess or chess.com, a PGN, or just type the moves so far; below the tool I explain how to read what it tells you, and when the engine's move is not the move you should play.
How to Get a Position Into the Tool
The fastest way is a FEN, the one-line text description of a position. On lichess, open the analysis board, play the moves or set up the position, and copy the FEN from the box under the board. On chess.com, open any game, click the share icon and choose "FEN". Paste it into the box above. A FEN looks like r1bqkbnr/pppp1ppp/2n5/4p3/4P3/5N2/PPPP1PPP/RNBQKB1R w KQkq - 2 3; the letter after the board, w or b, is whose turn it is, and the tool orients the board accordingly.
If you have a whole game, paste the PGN instead, headers and all, or simply type the moves played so far: 1.e4 c5 2.Nf3 d6 3.d4. The tool plays them out and analyzes the final position. Leave the box empty and it analyzes the starting position, which is a good way to see what the engine thinks of 1.e4 against 1.d4 (it thinks they are equal).
Depth controls how far ahead the engine looks. Depth 12 answers instantly and is enough to spot a blunder; depth 18 is a serious club-level answer in a few seconds; depth 24 takes longer and is what you want for a critical endgame or a sharp tactical position. The engine reports the depth it actually reached, so you always know how much to trust the number.
How to Read the Evaluation
The evaluation is always from White's point of view. +1.5 means White is about a pawn and a half better; −0.3 means Black is slightly better; 0.0 is equal. As a rule of thumb, anything inside ±0.5 is a normal game, ±1 is a clear advantage that a strong player converts most of the time, ±3 is winning, and M5 means White mates in five moves at best play (−M5 for Black).
The three lines are the engine's ranking of the candidate moves, each followed by its expected continuation. When the first and second lines are within 0.2 of each other, the position has two good moves and the choice is yours; when the first line is a full point better than the second, there is only one move, and if you did not see it, that is what to study.
When the Engine's Best Move Is Not Your Best Move
As a grandmaster I use engines every day, and the mistake I see students make is treating the top line as the answer. It is the answer for a computer. Three cases matter for a human:
The engine's move needs an engine to follow it up. A +0.8 that comes from a sacrifice with a twelve-move only-move sequence is worth less than a +0.5 with a plan you understand. If you cannot explain why the move is good in one sentence, look at the second line.
The evaluation hides the practical difficulty. A position rated 0.0 can be trivial for one side and a minefield for the other. The tool tells you the objective truth; it does not tell you which side is easier to play, and against a human that is often the more important question.
Engines do not play the opponent. In a lost position the engine's best move is the one that loses slowest; your best move is the one that gives the opponent the most chances to go wrong. The engine is honest about the eval and silent about the swindle.
The right way to use this tool, then, is as a second opinion: decide on your move first, then check. If you agree with the engine, good. If you disagree, the interesting work is understanding why, and that is what turns a calculator into a coach.
Frequently Asked Questions
What is the best chess move calculator?
Any tool that runs a modern engine, and this one runs Stockfish 18 in your browser, the same engine chess.com and lichess use for analysis. The difference between calculators is not the engine but what they let you do with the result; this page adds the explanation of how to read it.
Is the next-move tool free?
Yes, completely: no signup, no daily limit, no upload. The engine runs on your own device, so your positions never leave your browser.
Can I paste a position from chess.com or lichess?
Yes. Copy the FEN from either site's analysis board (chess.com: share icon, then FEN; lichess: the FEN box under the board) and paste it into the tool. A PGN of the whole game works too.
Which depth should I use?
Depth 18 for almost everything. Use 12 when you only want to know whether a move blunders material, and 24 for endgames and sharp tactical positions where the first move of a long forced line decides the game.
Does the tool tell me the best move for Black?
Yes. The side to move is read from the position: if the FEN says it is Black's turn, or the PGN ends after a White move, the best move shown is Black's, and the board flips so Black is at the bottom.