About the Sudoku
Sudoku is the number puzzle where every row, every column and every 3 by 3 box must contain the digits 1 to 9 exactly once. This game makes a fresh puzzle each time, in three levels (easy, medium and hard), and every puzzle has exactly one solution, so you never need to guess. Click a square and type a number or use the number pad, highlight matching numbers, see conflicts in red, use a hint when you are stuck and check your work. A timer counts how long you take. Everything runs in your browser.
Updated October 2026
How to use the Sudoku
- 1Choose a difficulty; a new puzzle is made.
- 2Click a square and type a number, or press a number on the pad.
- 3Use the highlights to see the same number and the row, column and box.
- 4Press Check to find mistakes, or Hint for help.
- 5Fill the grid correctly to win.
The two basic techniques
Most easy puzzles can be solved with two ideas. Scan a row, column or box for a missing number and see where it fits (a hidden single). Or look at a square and see which numbers are still possible in it (a naked single). The page shows the possible numbers for the selected empty square to help you learn.
Habits of strong solvers
Work methodically instead of guessing. Go through each number from 1 to 9 and find its places in every box. When you are stuck, note the squares that have two candidates and look for chains. Do not fill a number unless you can explain why it is the only choice.
- Scan rows, columns and boxes for the missing numbers
- Use the highlights to see where a number already is
- Check your work before you move on
- Use hints sparingly to learn
Solving a puzzle from a newspaper
If you have a puzzle on paper that you cannot finish, type it into the Sudoku Solver, which finds the answer and tells you if the puzzle has more than one solution. Use it to check your own answer.
Related tools and games
Use the Sudoku Solver for any puzzle, play 2048, try Minesweeper and the Maze Generator for printable puzzles. The Word Search Generator makes word puzzles.
Features
- Easy, medium and hard puzzles
- Each puzzle has exactly one solution
- Highlights, conflict marks and a possible-numbers hint
- Hint and Check buttons
- Timer
- Keyboard and touch support
Frequently asked questions
How do I play Sudoku?
Fill each empty square with a number from 1 to 9 so that no number repeats in any row, column or 3 by 3 box.
Is there only one solution?
Yes. The generator removes numbers only while the puzzle stays uniquely solvable, so every puzzle can be solved by logic.
What are the difficulty levels?
Easy gives about 40 numbers, medium about 32 and hard about 26. Fewer clues usually means harder logic.
What does Hint do?
It fills in one correct square for you, and the hint count is shown with your result.
What does Check do?
It marks every number that you entered that is wrong, but does not fill anything in.
How do I start if I am stuck?
Look for a number that can go in only one square of a row, column or box, or for a square where only one number fits.
Can I use the keyboard?
Yes. Type 1 to 9, use the arrow keys to move and Backspace or Delete to clear a square.
Can a puzzle ever be unsolvable?
Not here. Each puzzle is built from a finished grid and checked to have a single solution, so a mistake can only come from a wrong number you entered.
How long should a puzzle take?
An easy puzzle takes most people 5 to 10 minutes, a medium one 10 to 20 and a hard one 20 minutes or more. Do not worry about the clock while you are learning.
Does it save my game?
The game lasts while the page is open. Reloading or leaving makes a new puzzle.
Is it free?
Yes. No sign-up or download is needed.