What are the rules of Sudoku?

Fill the 9x9 grid so that every row, every column and each of the nine 3x3 boxes contains the digits 1 to 9 exactly once. Some cells are filled in to start. There is no arithmetic involved; it is pure placement logic, and there is only ever one correct answer.

Does every puzzle have just one solution?

Yes. Each puzzle is generated and then verified to have a single unique solution before you see it, so you never reach a point where you have to guess between two valid answers. If your grid is full and correct, it is the one intended solution.

What is the difference between Easy and Expert?

The difficulty is set mainly by how many starting numbers you get. Easy puzzles give you around 40 clues and can be solved by direct scanning. Expert puzzles leave you roughly 24, so you lean on notes and harder techniques to make progress.

Is this free, and do I need an account?

It is completely free and there is no account or sign-up. You just open the page and play. There is no paid tier and no limit on how many games you start.

Sudoku

Play Sudoku free in your browser, from Easy to Expert. Fill the grid so every row, column and 3x3 box holds the digits 1 to 9 with no repeats. Add pencil notes, check for mistakes, take a hint when you are stuck, and race the timer. Every puzzle has exactly one solution.

Free, with no ads in the way
No sign-up, no app
Plays instantly in your browser
Scores stay on your device
Works offline after first load

Read the guide: How to Play Sudoku

Level0:00

Click a cell, then type 1 to 9 or use the pad. Turn on Notes to pencil in candidates. Check flags any wrong entries; Hint fills one correct cell.

How to use it

1
Pick a difficulty

Choose Easy, Medium, Hard or Expert. Easy boards give more starting numbers; Expert leaves you far fewer and needs more careful logic.
2
Fill the grid

Tap a cell and type a digit. Switch to Notes to pencil in the candidates for a square while you work it out.
3
Check and finish

Use Check to spot any wrong entries, or Hint to reveal one correct cell. Finish the grid before the timer climbs too high.

When it comes in handy

A daily brain workout

A few puzzles a day keep you practising the kind of patient, step-by-step logic Sudoku is built on.

Wind-down time

Sudoku is quiet and screen-friendly, a calm way to switch off without anything flashing for your attention.

Learning the game

Start on Easy with notes and hints turned on, then drop the hints as the patterns start to feel familiar.

Free, private & 100% in your browser

The game runs right here in your browser. There is no sign-up and no limit on how many rounds you play, your scores stay on your own device, and once the page has loaded it keeps working even with no connection.

Frequently asked questions

What are the rules of Sudoku?: Fill the 9x9 grid so that every row, every column and each of the nine 3x3 boxes contains the digits 1 to 9 exactly once. Some cells are filled in to start. There is no arithmetic involved; it is pure placement logic, and there is only ever one correct answer.
Does every puzzle have just one solution?: Yes. Each puzzle is generated and then verified to have a single unique solution before you see it, so you never reach a point where you have to guess between two valid answers. If your grid is full and correct, it is the one intended solution.
What is the difference between Easy and Expert?: The difficulty is set mainly by how many starting numbers you get. Easy puzzles give you around 40 clues and can be solved by direct scanning. Expert puzzles leave you roughly 24, so you lean on notes and harder techniques to make progress.
Is this free, and do I need an account?: It is completely free and there is no account or sign-up. You just open the page and play. There is no paid tier and no limit on how many games you start.