Play Sudoku Online — Free Number Puzzle
Sudoku is the world's favourite number puzzle: fill the 9x9 grid so that every row, every column, and every 3x3 box contains the digits 1 to 9 exactly once. Three difficulty levels, from gentle to fiendish. Play Sudoku free in your browser.
How to Play Sudoku
Some squares start filled. Using logic alone, work out the missing digits so the whole grid obeys the rules — no guessing required.
The rules
- Each row must contain 1 to 9 with no repeats.
- Each column must contain 1 to 9 with no repeats.
- Each 3x3 box must contain 1 to 9 with no repeats.
- Click a square and type or tap a number; use pencil marks to note candidates.
Difficulty
Choose from three levels — fewer starting clues make for a harder puzzle.
Strategy & Tips
- Start with the squares that have only one possible number.
- Scan each row, column and box for a digit that fits in just one place.
- Use pencil marks to track candidates in the trickier squares.
- Look for pairs — two squares sharing the same two candidates rule those numbers out nearby.
- Work from the most-filled areas; they constrain the puzzle the most.
Frequently Asked Questions
What are the rules of Sudoku?
Fill the 9x9 grid so that every row, every column, and every 3x3 box contains the digits 1 to 9 exactly once.
Does Sudoku require guessing?
No — every puzzle here can be solved by logic alone. If you find yourself guessing, there's usually a deduction you've missed.
Are there difficulty levels?
Yes — three, with fewer starting clues on the harder levels.
Is Sudoku free to play?
Yes — free, with no sign-up or download.
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