Nonogram Solver

Stuck on a nonogram from a puzzle book, app, or another site? Enter its row and column clues below and this tool will solve it for you using the same logic engine that powers every puzzle on Nonogram Hub — or switch to "try it yourself" and solve it on an interactive board with the same fill/mark tools used across this site.

Width (columns)Height (rows)

Row clues

One line per row, numbers separated by spaces (e.g. "3 1"). Leave a line blank for an empty row.

Column clues

One line per column, numbers separated by spaces. Leave a line blank for an empty column.

FAQ

How do I enter clues from a puzzle book?

Set the width and height to match the puzzle's grid, then type each row's numbers on its own line in the row clues box (in order, top to bottom), and each column's numbers on its own line in the column clues box (left to right). Separate multiple numbers in the same line with a space, like "3 1".

What if my puzzle doesn't have a unique solution?

A well-formed nonogram always has exactly one solution. If this tool reports more than one, either a clue was mistyped, or the source puzzle itself is flawed — double-check the numbers against the original.

Is there a size limit?

The solver is capped at a few seconds of computation to keep this page responsive for everyone. Very large or deliberately ambiguous grids may time out — most real puzzle-book nonograms solve in well under a second.

Can I solve the puzzle myself instead of having it solved for me?

Yes — after entering your clues, use "Try it yourself" to get the same interactive grid used across this site, with fill and mark tools, on your own puzzle's clues.

Can I print this puzzle?

Yes — after entering your clues, click "Download printable PDF" to get a blank grid with the clues laid out for solving on paper. If the puzzle has a unique solution, you can also download a version with an answer key on a second page.

Read the full how-to-play guide →

How this solver works

Everything runs in your browser. The clues you type are never uploaded to a server — the solving engine is JavaScript executing on your own machine, so it works the same whether the puzzle came from a magazine, a screenshot, or a grid you designed yourself.

The engine reasons line by line, the same way a person does. For each row and column it works out every arrangement of blocks the clue still permits, then fills in the cells that are filled in every one of those arrangements, and crosses out the cells that are empty in every one of them. Because deducing a cell in a row also constrains the column crossing it, the process repeats until nothing new can be deduced. Where pure deduction stalls, it falls back on a bounded search rather than guessing blindly.

It does not stop at the first answer it finds. It deliberately looks for a second, different solution — which is what lets it tell you whether your clues have exactly one answer, more than one, or none at all. A nonogram with two valid solutions is a broken nonogram: usually a mistyped number, occasionally a genuine flaw in the source puzzle. Solving is capped at a few seconds so the page stays responsive, and nearly every real puzzle-book nonogram finishes well inside that.

This is the same engine every puzzle on Nonogram Hub is validated with before it is published — which is why the daily puzzles are always solvable by logic alone, with no guessing required.

Learn to solve them yourself

A solver is useful for checking an answer or rescuing a puzzle you're stuck on — but nonograms are more fun when you don't need one. These guides cover, step by step, the techniques the engine above is applying automatically:

Using it to check rather than to finish

Most people arrive here wanting the answer, and the tool will give it. The more useful mode is the other one: type the clues from a puzzle you are already halfway through, solve, and compare. If your grid and the solver's disagree, you now know a mistake exists and roughly where — which is far more actionable than staring at a board that has stopped moving.

That matters most on large grids. A wrong cell on a 10×10 usually contradicts itself within a few deductions, but on a 20×20 it can sit quietly for twenty minutes and only surface when a line at the far side refuses to resolve. Checking against a known-correct grid turns a half-hour hunt into a glance.

If you would rather not see the finished picture, use the print option instead of solving. The export only needs valid clues, so you can produce a blank sheet with the clue numbers laid out around it and no answer key attached.

When it says your puzzle has more than one answer

This is the result worth understanding, because it is the one that saves an evening. A well-formed nonogram has exactly one solution reachable by logic alone. If the solver reports two, the puzzle as typed cannot be solved by deduction — at some point the only way forward would be to pick a branch and hope.

In practice that means one of two things, and they are worth checking in order. Most often a clue was mistyped: a 12 entered as a 1 2, or a line skipped so everything below it shifted up by one. The solver checks the number of lines against the grid height and width, which catches the second kind, but not the first.

The other possibility is that the source puzzle is genuinely flawed. Printed collections do contain misprints, and an ambiguous nonogram looks entirely reasonable until you are deep inside it. Being able to prove it was the book rather than you is the single most useful thing this tool does that a pencil cannot.

Designing your own puzzle

You do not need an existing puzzle to use this. Type any set of clues and the solver will tell you whether they describe exactly one picture, several, or none — which is the whole problem of nonogram design in one answer. Drawing a pleasing shape is the easy half; guaranteeing that the clues it produces have a unique solution is the half that needs checking.

The same engine validates every puzzle published on this site before it goes live, which is why nothing in the catalog ever requires a guess. If you are making puzzles for someone else, run them through here first — an ambiguous grid is not a harder puzzle, it is a broken one, and the person solving it has no way to tell the difference until they are stuck.

Solving is capped at four seconds so the page stays responsive. A timeout is not a verdict: it usually means the grid is large and unusually loose, and it is worth re-checking the clues before assuming the puzzle is at fault.