Tap a cell, then tap a number. Notes mode writes small pencil marks. Every puzzle has exactly one solution.
SepoGames › Sudoku
Sudoku is a number puzzle you can play right here, for free. You get a 9×9 grid. Some squares already have numbers. Your job is to fill in the rest. Every puzzle on this page is made fresh when you press "New puzzle", and the computer checks that it has exactly one solution. So you never have to guess. Every number can be found with logic.
That is all. There is no maths in Sudoku. You could use letters or colours instead of numbers and the puzzle would work the same way.
On a computer you can also type 1–9, use the arrow keys, Backspace to erase, N for notes and U for undo.
| Level | Numbers given | Hints | What it feels like |
|---|---|---|---|
| Easy | 42 | 5 | Most squares have only one choice. Great for learning. |
| Medium | 34 | 4 | You need to scan rows and boxes more carefully. |
| Hard | 29 | 3 | Pencil notes start to really help. |
| Expert | 25 | 2 | Long chains of logic. Take your time. |
Your best time for each level is saved on your device. Try to beat it.
Look at the pad. If a number already appears seven or eight times, the last spots for it are easy to find. Fill those first.
Pick a box. Ask: where can the 5 go in this box? If the other 5s in the same rows and columns block every square but one, that square is the 5. This is called a hidden single.
Pick one empty square. Check its row, column and box. If eight numbers are already used, the ninth one must go there. This is a naked single. Easy and Medium puzzles are mostly solved with these two tricks.
Do not try to keep all the options in your head. Write them down with Notes. When you place a correct number, the page removes that number from the notes in the same row, column and box for you.
If two squares in the same row can only be 3 or 7, then 3 and 7 are "taken" by those two squares. No other square in that row can be 3 or 7. This often opens the next step.
Every puzzle here has one solution, so there is always a logical next step. If you feel stuck, look at a different box, or use one hint.
Sudoku trains focus, patience and working memory. You keep a few facts in mind while you check rows, columns and boxes. Many people like it as a calm break, like a short walk for the mind. Studies on older adults link regular puzzles like Sudoku and crosswords with sharper thinking, but a puzzle is not a medicine. The honest benefit is simple: 10 quiet minutes away from scrolling, and a nice feeling when the last number fits.
Yes. It is free, with no download and no account. It works on phones, tablets and computers.
Yes. Each puzzle is checked by the computer before you see it. If a number could be removed and still leave more than one answer, it stays in the grid.
A red number does not match the solution. It counts as a mistake. Tap it and press Erase, or Undo.
Press Notes, then tap numbers. They show up small in the square. Press Notes again to go back to normal numbers.
Yes. Try our Daily Sudoku. Everyone gets the same puzzle each day.
Yes. Printable puzzle PDFs with answers are on our downloads page.
🛒 Like solving Sudoku on paper?
Books for every level – and a good pencil.
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