Sudoku

How to play Sudoku

Fill the grid so that every row, every column and every 3 × 3 box contains the numbers 1 to 9 exactly once. Some numbers are given at the start; your job is to work out the rest.

Filling in squares

• Tap a square, then tap a number — or type it on your keyboard. Arrow keys move between squares.
• Switch on Pencil to jot small possible numbers in a square while you think. When you place a number, matching pencil marks in the same row, column and box tidy themselves away.
• Each number button shows how many of that number are still to place.

Hints that teach

Press Hint and the game points to a square you can solve next and explains why — for example, "in this row, 7 can only go here". If you've made a mistake, the hint shows you where first.

The four levels

Tips

• Start with rows, columns or boxes that are nearly full.
• Take one number at a time and look for where it must go in each box.
• If only one number fits a square, it belongs there.
• On harder puzzles, fill in pencil marks for a whole box before deciding anything.

Prefer paper?

Every level comes as a free large-print sheet with an answer key on the second page — big, clear numbers with room to write in. Print an easy, medium, hard or expert puzzle, or browse all our printables.

Questions

Do I ever have to guess?

Never. Every puzzle has exactly one solution, and we check that each one can be finished by logic alone, using only the techniques its level calls for.

Will it tell me if I make a mistake?

Only if you want it to. Turn on "Show mistakes in red" in Settings, or press Hint — it always points out a wrong number before anything else.

Is my puzzle saved?

Yes, automatically, including your pencil marks. Close the page and come back any time on the same device.