Classic sudoku — play free online (including a mode for absolute beginners)

No cages, no sums — just the classic 9×9 grid, in four difficulties from "genuinely teaches you the game" to properly hard. 400,000 puzzles, every one verified to have exactly one solution.

Never played? Start with Coward's Sudoku

Our gentlest mode isn't just easy — it's machine-verified to be solvable one obvious step at a time. At any moment in a Coward's puzzle there is always at least one cell with only one possible digit, so you can complete your first ever sudoku without guessing, without techniques, and without reading a single guide. Stuck anyway? The 💡 Hint button points at the next obvious cell.

Open Coward's Sudoku →

The rules (all three of them)

• Every row contains the digits 1–9 exactly once.
• Every column contains the digits 1–9 exactly once.
• Every 3×3 box contains the digits 1–9 exactly once.

That's the entire game. The given digits get you started; logic does the rest.

Four difficulties

• Coward's — ~47 givens, always an obvious next move. The teaching mode.
• Classic Easy — 40 givens. A normal easy sudoku.
• Classic Medium — 32 givens. The newspaper standard; pencil marks recommended.
• Classic Hard — around 26 givens. Proper thinking required.

Puzzle numbers are permanent — Classic Medium #4,821 is the same puzzle for everyone, forever — so you can send a friend a link and race them. Progress saves automatically, there's a dark mode, and every puzzle prints as a clean blank grid.

Ready for more?

When classic sudoku stops scaring you, the site's main event is killer sudoku — same grid, no given digits, cages that add up. It sounds harder than it is, and the daily puzzle is the friendly way in.