Sudoku
Classic 9×9 Sudoku in four levels, from easy to expert — with pencil notes, undo, hints that explain the next logical step, a new daily puzzle, printable puzzle sheets and a solver for puzzles from the newspaper.
At a glance
- Four levels — Easy, Medium, Hard and Expert — graded by the techniques a person needs, from simple singles to pairs, pointing pairs, X-Wing and XY-Wing.
- Every puzzle is newly made, has exactly one solution and can be solved by logic alone, without guessing.
- Hints explain the next step — which digit goes where and why — and point out a wrong digit first if you have one.
- Pencil notes, automatic notes, undo, mistake highlighting, a timer with pause, and your best time for each level.
- A new daily puzzle that is the same for everyone, with a streak counter.
- Print 1 to 48 puzzles as a PDF (1, 2, 4 or 6 a page, A4 or US Letter) with answer pages, or solve a puzzle from a newspaper or app.
Step by step
How to play Sudoku
- 1
Know the rule
Fill every row, every column and every 3×3 box with the digits 1 to 9, each exactly once.
- 2
Pick a cell
Tap a cell (or use the arrow keys) and tap a number — or type it.
- 3
Use notes
Switch on Notes to pencil in the digits a cell could be, or press Auto notes.
- 4
Get unstuck
Press Hint to see the next logical step and why it works.
Features
Everything you need, nothing you don’t
Always solvable by logic
One solution and no guessing — each puzzle is checked by a solver that thinks like a person.
Hints that teach
See the technique behind each hint, from hidden singles to X-Wings.
Pencil notes
Jot candidates by hand, fill them in automatically, and they tidy themselves as you place digits.
Daily puzzle
A fresh medium puzzle every day — the same for everyone — and a streak to keep up.
Print and play
Make a PDF of new puzzles with answers for travel, classrooms or the newspaper habit.
Your game is kept
Close the tab and carry on later; the game is saved in this browser.
Sudoku techniques, from easy to expert
| Technique | Level | What it means |
|---|---|---|
| Naked single | Easy | A cell where only one digit is still possible. |
| Hidden single | Easy | A digit that fits in only one cell of a row, column or box. |
| Pointing pair / box-line | Hard | A digit locked into one line of a box (or one box of a line) can be removed elsewhere. |
| Naked / hidden pair and triple | Hard | Two or three cells that share the same two or three digits rule those digits out of the rest of the unit. |
| X-Wing | Expert | A digit limited to the same two columns in two rows can be removed from the rest of those columns. |
| XY-Wing | Expert | Three two-digit cells that force a digit out of any cell that sees both ends. |
FAQ
Frequently asked questions
Is this Sudoku free?
Does every puzzle have one solution?
What makes a Sudoku hard?
Can I solve a Sudoku from the newspaper?
Is my game saved?
Keep going
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