Chess Move Calculator
Enter a position and the calculator returns the engine evaluation, the strongest move, and the continuation it expects. Everything is computed on your own device.
What the evaluation number means
Chess engines score a position in pawns, from White's point of view. A score of +1.0 says White holds an advantage worth about one pawn, and -3.0 says Black is a piece up or has an equivalent positional grip. 0.0 is balanced.
Useful reference points for a club player: under 0.5 in either direction is effectively equal and the game is still a game. Around 1.5 the better side should convert with accurate play. Past 3.0 the position is usually decided, though plenty of games at that score are still lost by the side that is winning.
M5 and similar mean forced mate, and the number is how many moves it takes. A mate score is not an evaluation in pawns at all, which is why it is displayed differently.
How to calculate a position
- Set the pieces by playing moves, or paste a FEN string.
- Confirm the side to move, which changes the answer completely.
- Choose a depth and press the button. The result shows the evaluation, the best move, and the expected continuation.
There is no account, no sign in, and no limit on how many positions you can check. Nothing on this page is gated.
Depth changes the number
Depth is how many half moves ahead the engine searches before it commits to an answer. Depth 10 is quick and already stronger than almost every club player. Depth 18, the setting Chess DNA uses when it analyses your imported games, is far more reliable in sharp tactical positions but takes noticeably longer in a browser tab. Start at the balanced setting and raise it when the position is unclear.
If the evaluation swings a lot between depth 10 and depth 18, that is a signal in itself: the position is tactically sharp, and a human is far more likely to go wrong in it than in one where the number barely moves.
The engine is Stockfish 17.1, the same open source engine that powers analysis on Lichess and inside Chess DNA. It runs as WebAssembly in your own browser, so your position is never uploaded anywhere. The first search downloads roughly 7 MB of engine; after that it is cached and every later search starts instantly.
From one position to your whole game
Calculating one position is a spot check. Running the same calculation on every move of a finished game is a review, and that is where the useful information lives, because it shows the exact moment the game turned. The free game review tool does that for a whole PGN, and it uses the same engine as this page.
Frequently Asked Questions
What is a chess move calculator?
It is a chess engine with a simple front end: you give it a position, it searches ahead and returns the strongest move along with a numeric evaluation of the resulting position. This one uses Stockfish 17.1 and runs entirely in your browser.
How accurate is the evaluation?
At the depths offered here the evaluation is reliable for practical purposes and far beyond human strength. It is not a proof: engines can misjudge deeply locked positions and some endgames where a tablebase is the only true authority.
Is a positive score good for me?
A positive score is good for White and a negative score is good for Black, regardless of who is to move. If you are playing Black, you want the number to be negative.
Can I calculate a position from a photo or a diagram?
Not directly. Set the pieces on the board above to match the diagram, which takes under a minute, or paste the FEN if the source provides one.
Does it cost anything?
No. There is no account, no daily cap, and no payment. The engine runs on your device.
