Sudoku
A new puzzle every time you open the page or press New puzzle. Move to a square and type a number from 1 to 9, or press a square and then a number button. Backspace clears a square.
The grid
Numbers
Nothing is saved: no scores, no progress, no cookies. Reload and the game starts again.
About this game
How to play
- The grid is nine squares by nine, split into nine boxes of three by three. Some numbers are given at the start.
- Fill every empty square with a number from 1 to 9, so that each row, each column and each box holds every number exactly once.
- Every puzzle here has exactly one solution, so there is always one right answer.
- Press Check at any time: it counts the empty squares and marks every square that does not match the solution with a dashed outline. Clear my answers removes your numbers and keeps the given ones. New puzzle makes a fresh one.
What the three levels change
- Easy
- About 40 numbers are given, and every square can be found with the simplest step: a square that can hold only one number, or a number that fits in only one square of a row, column or box.
- Medium
- About 32 numbers are given.
- Hard
- As few numbers as the puzzle allows while keeping one solution — usually 24 to 28.
Keyboard and screen readers
- Tab reaches every square. Type a number from 1 to 9 to fill it; Backspace, Delete or 0 empties it.
- Or press a square, then one of the number buttons under the grid. Erase empties the square.
- Each square’s name gives its row, its column and its number, and says whether the number was given or is yours. Every change is read out from the line under the grid.
An odd fact about this game
A sudoku needs at least 17 given numbers to have only one solution. In 2012 Gary McGuire, Bastian Tugemann and Gilles Civario proved it with an exhaustive computer search that found no 16-number puzzle with a single answer.
Source: McGuire, Tugemann and Civario, “There is no 16-Clue Sudoku”, 2012