Sudoku
Fill the grid so every row, column and box has 1 to 9.
How to play Sudoku
Goal: Fill every empty cell with a number from 1 to 9.
- 1Each row must contain 1 to 9 exactly once.
- 2Each column must contain 1 to 9 exactly once.
- 3Each 3×3 box must contain 1 to 9 exactly once.
- 4Wrong numbers turn red and count as a mistake.
On a computer
Click a cell, then type 1 to 9. Arrow keys move, Backspace erases.
On a phone
Tap a cell, then tap a number below the grid.
Play free Sudoku online in easy, medium and hard. Every puzzle is freshly generated with one unique solution.
About Sudoku
Sudoku is a number placement puzzle played on a nine by nine grid split into nine smaller three by three boxes. Some cells start filled in. You fill the rest so that every row, every column and every box contains the numbers 1 to 9 exactly once. No math is needed. It is pure logic.
Number grid puzzles like this have been printed since the late 1970s, and the modern name Sudoku comes from Japan, where the puzzle became popular in the 1980s. It spread worldwide in newspapers in the 2000s. Our free Sudoku generates a fresh puzzle every time you start, and each puzzle is checked to have exactly one solution, so you never need to guess.
Choose Easy, Medium or Hard depending on how much time you have. Sudoku is a calm, focused way to keep your mind active, and you can play it on your phone or computer with no download and no sign up.
Sudoku tips and strategy
- Start by scanning each number from 1 to 9 across the boxes. If a number can only fit in one cell of a box, place it.
- Look for naked singles: cells where only one number is possible after you rule out its row, column and box.
- Work on the rows, columns and boxes that are already most filled. They give you the most information.
- If two cells in a box can only hold the same two numbers, those numbers cannot go anywhere else in that box. Use that to clear other cells.
- Tap a filled number to highlight every copy of it on the board. Gaps in the pattern often reveal the next move.
- Wrong numbers turn red and count as mistakes, so if you are unsure, leave the cell empty and come back later.
- On Hard, slow down. Every puzzle has a logical path, so if you feel stuck, re-scan instead of guessing.
Sudoku FAQ
Is Sudoku good for your brain?
Sudoku exercises logic, memory and concentration, and many people use it to keep their mind active. It is a healthy habit, but it is not a medical treatment.
Do you need math to solve Sudoku?
No. The numbers are only symbols. You could replace them with letters or colors and the logic would be the same.
Does every Sudoku have one solution?
Well made puzzles do. Every puzzle in our game is checked by the generator to have exactly one solution.
What is the difference between Easy and Hard?
Harder puzzles start with fewer given numbers, so you need longer chains of logic to find each next move.
Can I play Sudoku on my phone?
Yes. Tap a cell, then tap a number below the grid. It works in any phone browser with no app.