Sudoku
Fill the grid so every row, column and box holds each number once. Start small with a 4×4, or take on the classic 9×9. Every puzzle has exactly one answer, and you never need to guess on easy and medium.
Daily puzzle
Today's Sudoku
A medium 9×9 puzzle, the same for everyone today.
New puzzle
You haven't solved one at this level yet.
How to play
- Every row, every column and every box must contain each number exactly once: 1 to 4, 1 to 6 or 1 to 9, depending on the size.
- Pick a square, then a number. Use Notes to pencil in the numbers a square could be.
- A number that repeats in its row, column or box is shown in red with a !, so you can spot it straight away.
- Stuck? A hint explains the next logical step. If you've made a mistake, the hint finds it first.
- Your puzzle saves as you go, so you can leave and come back to it.
Two techniques that solve most puzzles
Only one number fits. Look at one empty square. If its row, column and box already use every number except one, that number goes there. Easy puzzles can be solved with this alone.
Only one square fits. Pick a number and a row, column or box that doesn't have it yet. If every other square there is ruled out, the number goes in the one that's left. Medium puzzles need this too. Hard puzzles need harder techniques, such as spotting pairs of squares that must share two numbers.
Is Sudoku math?
Sudoku doesn't use arithmetic: the numbers could just as well be letters or colours. It's logic, the same reasoning used in proofs and in computer science. A finished 9×9 grid is a special kind of Latin square, and mathematicians have counted how many there are: 6,670,903,752,021,072,936,960.
Your puzzles
Puzzles solved and your fastest times (with no hints) are saved in this browser only. No account, and nothing is sent anywhere.