Sudoku
Fill the grid so every row, column and box holds 1 to 9. Pure logic, no guessing.
Never a guess
Every puzzle has exactly one solution and is checked by our solver: you can always reach it by logic alone.
Hints that teach
Stuck? A hint shows where to look and names the technique — hidden single, pointing pair, X-Wing and more.
Daily challenge
A new puzzle every day, the same for everyone. Easy on Monday, toughest at the weekend. Keep your streak going.
Free, no sign-up
Notes, undo, auto-save and dark mode. Works on phone, tablet and desktop.
Five levels
Levels are graded by the techniques a puzzle needs, not just by how many numbers are given.
How to play Sudoku
- The grid has 9 rows, 9 columns and 9 boxes of 3 × 3 cells.
- Fill each empty cell with a number from 1 to 9.
- Each row, each column and each box must contain every number exactly once.
- The numbers already given cannot be changed. Every puzzle has exactly one solution.
Controls
- Select a cell, then press a number on the pad or keyboard. Turn on Notes to pencil in candidates.
- Keyboard: arrows move, 1–9 fill, Shift + number or N for notes, Delete erases, Ctrl+Z undoes, H gives a hint, P pauses.
Tips for solving
- Scan one number at a time: look for the only cell in a box where it can go (hidden single).
- If a cell has just one possible number left, fill it in (naked single).
- Use notes on harder puzzles. When two cells in a unit share the same two candidates, remove those numbers from the rest of the unit.
- Never guess. If you are stuck, a hint shows the next logical step.
New to sudoku?
From the rules and controls to X-Wing, learn step by step with diagrams of real puzzles.
Frequently asked questions
Is this Sudoku free?
Yes. Every level and the daily puzzle are free to play, with no sign-up and no download.
Does every puzzle have one solution?
Yes. Each puzzle is checked to have exactly one solution, and our solver confirms it can be solved by logic without guessing.
How are the difficulty levels decided?
By the hardest technique the puzzle needs. Easy and Medium need only singles; Hard adds pairs; Expert adds triples and X-Wing; Evil adds Swordfish.
How do notes work?
Turn on Notes and tap numbers to pencil them into a cell. When you place a number, it is removed from the notes in the same row, column and box. Auto notes fills in every candidate for you.
Is there a new puzzle every day?
Yes. The daily challenge changes at midnight in your time zone. Solve it on the day to grow your streak.