About Printable Sudoku
A puzzle generator built the way a small print shop would do it: set the run, pull a proof, print it.
What this is
This site makes printable sudoku PDFs to order. You choose how many puzzles, how hard, how many to a page and what size paper; it builds the puzzles and the document while you wait. It exists because most free printable sudoku on the web is a fixed PDF somebody made once — forty puzzles, one layout, take it or leave it — and that is rarely the sheet you actually wanted.
How the puzzles are made
Each puzzle starts as a complete, valid 9×9 grid produced by randomised backtracking. Clues are then removed one at a time in random order. After each removal a solver runs over what is left and counts solutions, stopping as soon as it finds a second one. If there are two, the clue is put back; only removals that leave the puzzle uniquely solvable are kept.
The solver uses bitmask candidate sets and picks the most constrained cell first, which is what makes running it after every single removal fast enough to be practical. This check is the expensive part of generation and it is the part plenty of free generators skip. We do not, because a sudoku with two answers is not a sudoku — it is a grid where at some point you have to pick.
Difficulty is defined by clue count: easy 38–45, medium 30–37, hard 25–29 and expert 20–24. The count for each individual puzzle is printed under its grid, so the label is backed by a number you can check.
Everything runs in your browser
There is no server involved in making your puzzles. The generator, the solver that verifies them and the code that lays out the PDF all run as JavaScript on your own machine — generation on a background thread so the page stays responsive during a large batch. Nothing about your run is uploaded, which is why the download is instant and why nothing you generate is ever stored anywhere. The privacy page spells out exactly what that means.
What it costs
Nothing. There is no account, no email capture, no trial, no watermark and no paid tier holding back the good puzzles. Print them for your class, your family, your care home or your newsletter — the grids are machine-generated and we make no ownership claim over what you produce.
Where it goes next
The obvious additions are more grid sizes, large-print layouts and puzzle variants. If you have printed a few sets and something about the sheets got in your way, that is the useful kind of feedback — the layout decisions here were made by printing a lot of pages and adjusting, and they will keep being made that way.