The Chess Calculator live

A set of free chess calculators. The first one is a best-move finder that runs Stockfish 18 in the tab. Paste a FEN or set the pieces. The move shows up in the largest type on the page.

Why

Most chess calculators are analysis boards with an engine tucked in a sidebar. I wanted the actual answer, the best move, to be the thing you see first. The position stays on your machine. Illegal FENs get named, not silently rewritten into a different game.

What it does

• Paste a FEN or drag pieces on the board.
• Stockfish 18 runs as WebAssembly in the tab. Nothing is sent to a server.
• The best move appears as soon as the engine has one, then gets stronger as depth climbs.
• Three candidate lines, with eval in pawns and the depth you actually got.
• Messy FENs from chat get trimmed and repaired in the open. An illegal position is named, not analysed as something else.
• On a phone the search stops after a few seconds so you are not left waiting.

What it is not

This is for study, puzzles you already finished, or a game after it ended. Using an engine while you play is cheating on chess.com, Lichess, and over the board.