# Chess best move calculator

> Paste a FEN, a PGN, or a Chess.com or Lichess link and see the best move, the evaluation, and two alternatives explained. Stockfish 18, free, no login.

URL: <https://thechesscalculator.com/best-move-calculator>

## What it answers

For one chess position, the page reports:

- The best move in standard algebraic notation, shown as the headline answer
- The evaluation, in pawns or as a mate-in-N when one exists
- Two alternative candidate moves with their own evaluations
- A short sentence in plain language explaining why the top move is good
- Search metadata: depth, nodes, elapsed time, and thread count

## How to use it

1. Open the calculator.
2. Paste a FEN, paste a PGN, paste a public Chess.com or Lichess game link, or drag pieces on the board.
3. Read the move in the largest type on the page.
4. Step backward and forward through an imported game to analyse any position in it.

## Engine

Stockfish 18 Lite with the NNUE evaluation network, compiled to WebAssembly and served from this domain rather than a CDN. Search depth is 18 and three candidate moves are reported. The multi-threaded build is used when the browser grants cross-origin isolation, and the single-threaded build otherwise.

## Limits worth knowing

- Analysis runs in the visitor's browser, so there is no API an agent can call for an evaluation.
- The first run downloads the engine binary. After that it is cached.
- It analyses one position at a time. It does not play a full game, drill tactics, or build an opening repertoire.
- Depth 18 is a strong club-level answer, not a correspondence-grade analysis. Deeper searches can change the third candidate move.

## Price

Free. No account, no rate limit, no paid tier.