How to play Sudoku
Sudoku is a number puzzle you solve with logic, not maths. You never add anything up. You only need to know which numbers are missing.
- Every row must hold each number once. In a 9×9 grid that means 1 to 9, with no repeats.
- Every column must hold each number once too.
- Every box (the squares with thick borders) must hold each number once.
Some numbers are printed in brown to start you off. Tap a square, then tap a number to fill it in. Your numbers show in blue so you can tell them apart.
Above: a solved 4×4 grid. Each row, column and 2×2 box has 1, 2, 3 and 4 exactly once.
Five puzzles every day
- Easy gives you lots of numbers. You can solve it by finding the one number that fits a square.
- Medium gives far fewer numbers. You will need to look for the only place a number can go in a row or box.
- Hard needs notes: at least one step uses a pair or a pointing trick (see the strategy guide).
- Kids 4×4 and 6×6 are small grids for children aged about 5 to 10, and a gentle warm-up for anyone new to Sudoku.
Everyone in the world gets the same five puzzles on the same date, so you can compare times with friends. Practice gives you unlimited new puzzles at every level.
Tips for solving faster
- Scan one number at a time. Pick a number, say 7, and look at each box. If only one square in a box can take a 7, it goes there.
- Find the nearly full rows. A row with eight numbers has exactly one gap and one missing number.
- Use notes on hard puzzles. Turn on Notes and write the small numbers each square could be. Placing a number clears it from the notes around it automatically.
- Stuck? Ask for a hint. The hint shows the next square you can fill and tells you why, so you learn the trick for next time.
Sudoku guides and printables
- How to play Sudoku
- Sudoku strategies
- Sudoku for kids
- 4×4 Sudoku
- 6×6 Sudoku
- Printable Sudoku PDFs
- All guides
Questions
Does every puzzle have exactly one answer?
Yes. A solver checks every puzzle before you see it. Each one has a single solution that you can reach by logic alone, with no guessing.
What counts as a mistake?
A number that doesn't match the solution turns red and counts as a mistake. There is no limit, so you can keep going. If you'd rather find your own errors, switch off "Show mistakes" in the stats and settings panel.
When does the new daily Sudoku come out?
At midnight in your own time zone. A countdown under a finished puzzle shows how long is left.
Is this Sudoku good for kids?
Yes. The 4×4 and 6×6 grids use only the numbers 1 to 4 or 1 to 6 and can always be solved one square at a time. Many teachers use them to build early reasoning. You can also print them for class.
Do I need an account or an app?
No. Sudoku runs in any modern browser on phone, tablet or computer. Your progress and stats are saved on your device only. You can add it to your home screen to play like an app.