Nonogram solver
A finished grid tells you the answer but not how to get there. This free nonogram solver explains every step and names the technique behind it. No account needed.
Numbers in order, such as 3 1. Enter goes to the next line.
Tap or drag to draw. The clues change to match your picture.
Step by step shows the solve one line at a time, with the technique for each step.
Every step explained
A finished grid gives you the answer without the reasoning. This solver works one row or column at a time, the way a person would, and says why each cell is filled or crossed out.
How to read a step
Each step names a line, its clue and the cells it decides. Cells count from the left in a row and from the top in a column. The technique says which reasoning decided them.
- Overlap
- Push a run as far left as it goes, then as far right. Cells it covers both times are filled.
- Exact fit
- The runs plus one gap between each pair fill the whole line, so the clue fits only one way.
- Edge
- Crosses, filled cells and the edge of the grid limit where a run can start, so some cells are covered wherever it sits.
- Line complete
- Every run is in place, so the rest of the line is empty.
- Can't be reached
- No run can get to these cells, so they're empty.
- Run complete
- A run as long as the biggest number can't grow, so the cells at its ends are empty.
- Gap too small
- A space between crosses is shorter than any run that could go there.
- Empty line
- A clue of 0 means the whole line is empty.
- Every fit
- The cells come out the same in every way the clue fits. It covers what the named techniques don't.
Mistakes in the clues
A typo in one clue can make a puzzle impossible. The solver names the row or column that can't fit, and tells you when the clues fit more than one picture or need a guess.
Questions
Is this nonogram solver free?
Yes. It's free, needs no account or app, and works on phones too.
Can it solve a nonogram from a photo?
No. Type the clues, or draw the picture and the solver works out its clues.
Does it solve colour nonograms?
No. It solves black and white nonograms, from 5 by 5 up to 20 by 20.
Why does it say my puzzle needs a guess?
Line logic decides cells from one row or column at a time. A few puzzles have a single answer that line logic alone can't reach, so the solver shows the answer and where the logic stopped.
New to nonograms? Read how to solve a nonogram, or play today's free nonogram.