Play Sudoku Online
Every puzzle is generated on the spot with a guaranteed unique solution. Pick your difficulty and dive in — your progress saves automatically.
How to play on this board
Click a cell and type 1–9, or use the number pad. Toggle Notes to jot down pencil marks — placing a correct digit automatically cleans related notes. Wrong digits count as mistakes and glow red until fixed.
Difficulty guide
| Level | Clues | Best for |
|---|---|---|
| Easy | ~42 | Beginners, warm-ups |
| Medium | ~34 | Most players, daily habit |
| Hard | ~29 | Confident solvers |
| Expert | ~25 | Advanced techniques required |
What Makes Each Difficulty Tick
Fewer clues, deeper logic
Difficulty in Sudoku comes from two things: how many clues you start with, and which solving techniques you need. Easy grids are packed with clues, so nearly every step is a simple "single" — a cell with only one possible digit. As the clue count drops, you're forced to hunt for hidden singles, pairs, and beyond.
Always fair, always solvable
Every puzzle generated here is verified to have exactly one solution. You never need to guess — pure logic will always get you there. If you want to level up your technique game, our solving guide walks through every strategy from scanning to X-Wing.
Five Tips to Get Better, Faster
- Scan in boxes first. Most early progress hides in boxes: pick a digit and see which box can only take it in one place.
- Use pencil marks sparingly. Only note candidates when a cell has three or fewer options — pages of tiny numbers slow you down.
- Work the crowded rows and columns. Units with the most clues constrain the most, so they crack first.
- Pause when stuck. A ten-second breather often reveals the pair you've been staring past.
- Finish what you start. Completing puzzles — even slowly — builds the pattern memory that speed comes from.