Sudoku
Fresh puzzles every time — solve in your browser and share the exact same puzzle with a code.
Puzzle preview
This is an example board. Starting creates a new puzzle with your settings.
Start a new puzzle with these settings
Current settings: 9×9 · Easy
Fill the grid without repeating numbers in any row, column or box. Sudoku puzzles here are graded by the solving techniques they need, not by how many cells are empty. Choose a level to practise placing numbers or comparing candidates.
Change settings
Open with a code
If you received a code, open this section and paste it here.
How to use
- Pick a grid size and difficulty, or paste a shared puzzle code, and press Start.
- Fill every row, column, and box so no digit repeats. The Notes, Show conflicts, Hint, and Undo buttons are there when you're stuck.
- When you finish, save your time to the rankings, share the exact same puzzle with a link or QR code, or print it on A4 with the answers included.
FAQ
Does every puzzle have exactly one solution?
Yes. Every puzzle is checked during generation to have exactly one solution, so there is always a single correct answer and never a broken or ambiguous grid.
Is it free? Do I need an account?
Completely free, with no sign-up and nothing to install. Puzzles are generated right in your browser, and there is no limit on how many you can play or print.
What do the difficulty levels mean?
Difficulty is graded by the solving techniques a puzzle actually requires: Starter needs simple singles only, Easy adds hidden singles, Medium adds locked candidates, Hard adds pairs and triples, and Expert goes beyond that ladder. 4×4 grids offer Starter, 6×6 up to Easy, and 9×9 all five levels.
Which size should kids start with?
The 4×4 grid uses only the digits 1 to 4 and is perfect for a first sudoku; 6×6 is a good next step before the classic 9×9. When printing, the small sizes fit several puzzles on one A4 page, which makes the pages handy as worksheets.
How do I challenge someone to the same puzzle?
Every puzzle has a code that encodes the entire grid. Share the link or QR code and the other person gets exactly the same puzzle. Then compare your times on that puzzle's own ranking board.
Can I print puzzles?
Yes. The A4 sheet fits one 9×9, two 6×6, or four 4×4 puzzles per page, plus an optional answer page. Each printed puzzle has a QR code you can scan later to play the same puzzle online.
Print sudokuIs anything stored on a server?
Playing works entirely in your browser: preferences and puzzles in progress stay in your browser’s local storage, and finished records are saved there automatically the moment you finish. Only when you choose “Post to global rankings” are your nickname, record, and puzzle code stored on our server and shown publicly.