About Sudoku
Play Sudoku online for free. Fill the 9×9 grid so every row, column, and 3×3 box contains the digits 1 through 9 exactly once. Every puzzle is generated fresh with a unique solution, from a quick Easy grid to a demanding Hard one.
The Rules
Fill the 9×9 grid so every row, column, and 3×3 box contains the digits 1–9 exactly once.
Step by Step
- Each row must contain the digits 1–9 with no repeats.
- Each column must contain the digits 1–9 with no repeats.
- Each of the nine 3×3 boxes must contain the digits 1–9 with no repeats.
- Tap a cell, then tap a number to fill it in — use notes to pencil in candidates.
- The puzzle is solved when every cell is filled and all three rules hold.
Tips & Strategy
- Start with rows, columns, or boxes that already have the most numbers filled in.
- Scan for cells where only one digit is possible — those are safe to fill immediately.
- Use pencil marks (notes) for cells with multiple candidates, then eliminate as you go.
- Look for a digit that can only go in one cell within a box, even if that cell has other candidates.
Frequently Asked Questions
Is this Sudoku free to play?
Yes. Play free in your browser with no account or download required.
Does every puzzle have a unique solution?
Yes. Every generated grid has exactly one valid solution, regardless of difficulty.
What's the difference between the difficulty levels?
Higher difficulties start with fewer filled cells and require more advanced deduction techniques to solve.
Do I need to guess to solve Sudoku?
No — every puzzle here is solvable through pure logical deduction. If you're stuck, it means there's a technique you haven't spotted yet, not that you need to guess.
What's the fastest way to get better at Sudoku?
Practice spotting 'naked singles' (only one candidate left for a cell) and 'hidden singles' (a digit that only fits one cell in a row, column, or box) before moving on to harder techniques.
