About this tool
Generates Sudoku puzzles with a unique solution, with several difficulty levels. Lets you reveal the solution, download as PNG to print, or copy as text for other tools. Useful for printing Sudoku sheets to solve by hand, always having new puzzles available, creating exercises for classes, or simply for fun.
How to use
- Pick the difficulty level.
- Click the button to generate a new puzzle.
- Solve on screen or download as PNG to print.
- If you get stuck, click reveal solution.
Frequently asked questions
- What defines difficulty?
- Mainly, how many cells are pre-filled at the start and how complex the techniques needed to solve are. Easy has more given cells and basic techniques (simple elimination). Hard has fewer cells and requires advanced techniques (X-Wing, Swordfish, etc.). All levels have a unique solution.
- Does each puzzle have exactly one solution?
- Yes, all generated puzzles are guaranteed unique-solution. That's fundamental in a good Sudoku: if there's more than one solution, it stops being a puzzle and becomes guesswork. The generator verifies this property before returning the puzzle.
- Can I generate 4x4 or 6x6 Sudoku for children?
- This tool generates classic 9x9 Sudoku. Variants like 4x4 (easier for children), 6x6, 12x12, or 16x16 aren't available. For child variants, look for specific generators.