Sudoku

How to play Sudoku

Sudoku is a placement puzzle with a simple rule: every row, every column, and every 3×3 box must contain the digits 1 through 9 exactly once. This version gives you a fresh puzzle from our bank each time you hit New puzzle. You can pencil candidate numbers with Notes and press Check to see whether the digits you have filled in are valid. Nothing is downloaded, and you do not need an account.

Most puzzles can be solved with a handful of techniques. Start with naked singles — a cell that has only one possible digit. Then look for hidden singles, where a digit can fit in only one cell of a row, column, or box. Notes help you track those candidates so you do not have to hold the whole grid in your head. Check is there as a safety net, not as a substitute for solving.

Select a cell and type a number, or tap the on-screen keypad. Use Notes when you want to mark possibilities without committing. Play it at a desk or on a phone; the grid is built for both.

Tips

• Fill every obvious single before you branch into harder patterns. A new single often appears after each placement.
• Use Notes in a crowded box so you can see when a digit is forced into one cell.
• If you get stuck, scan one digit at a time across the whole grid instead of staring at a single box.

Controls: keyboard, mouse, touch. No download and no sign-in required.

FAQ

Are these Sudoku puzzles free, and do they require a download?

They are free to play in your browser. There is no app to install and no sign-in. Each new puzzle comes from a bank on this site.

What does the Check button do?

Check verifies the numbers you have already entered. It will flag mistakes in filled cells so you can correct them and continue.

Can I add pencil marks?

Yes. Turn on Notes to enter candidate digits in a cell without committing to a final number.