Sudoku

A guide to your next puzzle

How to play Sudoku

Play classic 9×9 Sudoku in your browser for free. Fill the empty squares using logic, with notes, undo, checking and hints available while you learn.

1. Choose an empty square and enter a number from 1 to 9.
2. Every row, column and 3×3 box must contain each number once. The starting numbers cannot be changed.
3. Use notes to remember possible numbers, Undo to take back an entry, or Hint if you need a little help. Complete the board to finish.

Choose your challenge

Easy starts with more filled squares, Medium leaves more for you to solve, and Hard starts with fewer clues. Each generated puzzle has exactly one solution. The levels change the number of starting clues; solving difficulty can still vary.

A tip to get started

Find a row, column or box with only a few gaps. For each gap, rule out the numbers already in its row, column and box.

Can I make pencil notes in online Sudoku?

Yes. Turn on Notes, or press N on your keyboard, to mark possible numbers in an empty square. Use the arrow keys to move between squares.

Play for free on your phone or computer. No download or account is needed. Choose Next puzzle after a round to keep playing; words and clues can repeat.