Tool

Nonogram solver

By · Updated

Type the clues of any nonogram and solve it in your browser — all at once, or one line at a time with every step explained.

How the solver works

It solves the way a careful person does, just faster. For each row and column it works out every arrangement of the clue that still fits the cells already known, fills the cells that are filled in all of them and crosses out the cells that are empty in all of them. Then it moves to the next line. A change in one row is new information for the columns that cross it, so it keeps going round until nothing changes.

That single rule covers every technique in our guide How to Solve Nonograms: overlap, working from the edges, crossing out cells no run can reach. Press Step to watch it happen line by line.

When line logic is not enough

A well-made nonogram solves by line logic alone. If the solver stalls with open cells left, it checks the remaining possibilities and tells you which case you have: the clues need trial and error to finish, they fit more than one picture, or they contradict each other — usually a typo in one line. It also catches the simplest typo up front: the row clues and the column clues must add up to the same number of filled cells.

Tips for entering a puzzle

  • Copy the clues line by line from the puzzle; a blank line is skipped, so write 0 for an empty row or column.
  • Separators are flexible: spaces, commas or dots all work.
  • Stuck on one of our puzzles instead? Every board here has Check and Reveal buttons, and the step-by-step guide explains the techniques the solver uses.

Play

Practice what the solver does

Size 10x10 nonograms

Small boards where every technique is easy to see.

 Daily Daily nonogram

One fresh puzzle a day, the same for everyone.

 Size 50x50 nonograms

Big boards that still solve by logic alone.

FAQ

Solver FAQ

Can this solve any nonogram?

Any black-and-white nonogram up to 60×60. Most puzzles solve by line logic in a moment. If the clues need trial and error, or allow more than one picture, the solver tells you so instead of pretending.

How do I enter the clues?

One line per row in the first box and one line per column in the second, numbers separated by spaces — for example 3 1 2. Write 0 for an empty line. Row clues read left to right, column clues top to bottom.

Is my puzzle uploaded anywhere?

No. The solver runs entirely in your browser; the clues never leave your device.

Why does it say the puzzle needs guessing?

Line logic — overlap, edges, reach — settles every cell of a well-made nonogram. When it stalls, the clues either need trial and error or describe more than one picture. Every puzzle on this site is checked to solve by logic alone.