About Numberdoku

Numberdoku is a free site for number logic puzzles, starting with Calcudoku. There are no ads, pop-ups or accounts. It runs in any modern browser on a computer, tablet or phone.

Every puzzle is made by our own generator and checked by a solver before you see it, so it has exactly one solution that you can reach by reasoning.

Numberdoku is made by ChaCha Studio. You can find all our puzzle games at chacha.im.

Numberdoku is an independent project. It is not part of, affiliated with or endorsed by any other company, app or publisher, including the owners of KenKen®. The design, puzzles and code are our own.

Your progress is stored only in your own browser. See our privacy page for details.