Sudoku generator
Generate classic 9×9 sudoku puzzles with one unique solution. Choose easy, medium, or hard — each level removes a different number of givens (clues).
How to generate sudoku
1. Pick difficulty: easy, medium, or hard.
2. Click Generate until you like the layout.
3. Optionally enable “show answers” for a solution sheet.
4. Download PDF and print.
Difficulty guide
Easy — newcomers
More givens mean fewer empty cells. Good first puzzles where singles and obvious pairs appear often.
Medium — daily habit
Fewer clues require scanning rows, columns, and boxes together. Typical newspaper level.
Hard — experienced solvers
Many cells blank; solving may need pencil marks for candidates and advanced techniques beyond pure singles.
When to use this tool
• When you want unlimited fresh puzzles without buying books.
• When teachers need matching puzzle and answer PDFs.
• When you prefer paper puzzles over phone apps.
Structure of a 9×9 grid
Nine rows, nine columns, and nine 3×3 boxes (often outlined thicker in print). A valid sudoku never repeats a digit in any row, column, or box. Solvers cross-check all three constraints when placing a number.
Frequently asked questions
What are the sudoku rules?
Fill the 9×9 grid with digits 1–9 so each row, each column, and each of the nine 3×3 boxes contains all digits exactly once.
How do difficulty levels differ?
Each level removes a different count of clues from a complete valid grid. Hard puzzles start with fewer givens, so logic chains get longer.
Does every puzzle have one solution?
Yes. Puzzles are built from a full valid solution, then cells are cleared while keeping the grid solvable.
Can I print the answer key?
Enable “show answers” before downloading PDF — the file will contain the completed grid.
Are puzzles stored online?
No. Generation is local in your browser.