Nonogram Generator
Generate printable nonogram (Picross) puzzles with row and column clues, a verified logic-only solution and SVG export.
Clicking a square in the grid below edits the picture too, and the clues update as you draw.
Click a square to cycle it: blank → filled → crossed out. The clue for a line reads left to right (rows) or top to bottom (columns), and each number is the length of one solid block of filled squares, with at least one blank square between blocks.
- Grid
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- Filled squares
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- Fill share
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- Clue numbers
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- Difficulty
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How it works
A nonogram — also called a Picross, griddler, hanjie or paint-by-numbers puzzle — hides a
picture in a grid. The numbers beside each row and above each column list the lengths of the
solid blocks of filled squares in that line, in order, with at least one empty square between
consecutive blocks. A clue of 1 2 on a 10-wide row means one filled square, then
a gap, then two filled squares, with the rest empty. A line with no filled squares is written
as 0.
This generator draws a random picture from your seed, reads off the row and column clues, and then checks the puzzle with a line solver — the standard technique human solvers use. For every line it works out which squares are filled in every arrangement that fits the clue and which are empty in every arrangement, marks those, and repeats across rows and columns until nothing new can be deduced. If that finishes the grid, the puzzle has exactly one solution and needs no guessing, and the difficulty box says so. If it stalls, the puzzle would need trial and error, so with “Only puzzles solvable by logic” ticked the generator throws that picture away and tries the next seed (up to 40 tries).
Very sparse grids are the hardest to make logic-solvable — short scattered blocks give the solver almost nothing to overlap — so if you drop the density below about 30% expect the difficulty box to warn you that guessing may be needed. Switch the source to “From my own picture” to type or click your own design and see its clues instantly; that is the quickest way to build a nonogram of a letter, a heart or a space invader.
The seed makes everything repeatable: the same size, density and seed always produce the same puzzle, so you can share a seed and solve the identical grid. Download the blank puzzle as an SVG to print at any size, or the solution SVG as an answer key. Everything runs in your browser with plain JavaScript — no uploads, no sign-up, no ads.
Frequently asked questions
What do the numbers in a nonogram mean?
Each number is the length of one solid block of filled squares in that row or column, listed in order from left to right for rows and top to bottom for columns. Consecutive blocks are separated by at least one empty square, so a clue of "1 2" means one filled square, a gap of one or more empty squares, then two filled squares. A line with no filled squares at all is written as 0.
Are the generated puzzles always solvable without guessing?
With "Only puzzles solvable by logic" ticked, yes. Every candidate grid is run through a line solver — the same overlap-and-force reasoning people use — which repeatedly marks the squares that are filled in every arrangement fitting a clue and empty in every arrangement. If that finishes the whole grid the puzzle has exactly one solution and needs no guessing; if it stalls, the generator throws that picture away and tries the next seed, up to 40 tries. Very sparse grids (below about 30% fill) sometimes cannot be made logic-solvable, and the difficulty box says so plainly.
Can I make a nonogram from my own picture?
Yes. Switch the source to "From my own picture" and type your design one line per row using # for a filled square and . for an empty one, or just click squares in the grid to draw. The row and column clues update as you go, and the tool tells you whether your picture makes a puzzle that can be solved by logic alone. Then download the blank puzzle and the answer key as SVG files to print at any size.