Sudoku

1. Each row holds the digits 1 to 9 once.
2. Each column holds the digits 1 to 9 once.
3. Each 3 by 3 box holds the digits 1 to 9 once.
4. Given digits are fixed. A repeated digit is marked as a conflict.
5. The puzzle is solved when the grid is full with no repeats.

1. One of each. Every row, column and box needs the digits 1 to 9 exactly once.
2. Find the only option. An empty cell whose row, column and box already use eight digits can hold only the ninth.

• Tap a cell, then a digit on the pad
• Notes mode (or Shift with a digit) writes small candidates
• Arrow keys move, 1 to 9 place, Backspace erases, N toggles notes
• Z to undo, Y to redo, H for a hint

Easy puzzles fall to naked singles, medium ones need hidden singles, hard ones pairs or triples, expert ones an X-Wing or Swordfish, and master ones go beyond them. Every puzzle has exactly one solution.

Is Sudoku free to play?

Yes. Sudoku is free in the browser with no account needed, no download and no ads. Your progress is saved on your device.

How do you play Sudoku?

Each row holds the digits 1 to 9 once. Each column holds the digits 1 to 9 once. Each 3 by 3 box holds the digits 1 to 9 once. Given digits are fixed. A repeated digit is marked as a conflict. The puzzle is solved when the grid is full with no repeats.

How do the levels and difficulty work in Sudoku?

Easy puzzles fall to naked singles, medium ones need hidden singles, hard ones pairs or triples, expert ones an X-Wing or Swordfish, and master ones go beyond them. Every puzzle has exactly one solution.

Can I play Sudoku on my phone or tablet?

Yes. Sudoku works in any modern browser on phones, tablets and computers, with touch, mouse and keyboard controls.

Is there a daily Sudoku puzzle?

Yes. Every day there is a new daily puzzle, the same for every player, alongside unlimited numbered levels.