Terms of use

By using this site you agree to these plain-language terms. Last updated November 12, 2026.

The site is operated by the team behind ChessHelper (chesshelper.ai).

Using the calculator and guides

You may use the calculator and read the guides for free, for personal study, teaching and club use. Please do not resell the site's content or present it as your own.

Fair play

You may not use this calculator, or any tool we describe, to get help during a game against another person. Chess.com, Lichess, FIDE and US Chess all forbid it. Use the calculator for finished games, study positions and practice against bots or in analysis mode.

No warranty

The calculator and guides are provided as they are. Engine output can be wrong, especially at low depth, and tool prices and features change. We check our content carefully but make no guarantee that it is complete, accurate or current, and we are not liable for decisions you make based on it.

Open-source software

The calculator uses Stockfish 10 (GNU GPL v3) and chess.js (BSD license). Your rights under those licenses are not limited by these terms. See credits for sources and license texts.

Third-party sites and trademarks

We link to other websites for convenience and are not responsible for their content. Chess.com, Lichess, Stockfish and the other names mentioned belong to their owners; we are not affiliated with them.

Changes and contact

We may update these terms; the date above shows the latest version. Questions: [email protected].