About Sudoku
Sudoku is one of the world's most loved logic puzzles and consistently ranks among the top free puzzle games. Our version focuses on a clean, readable board with smart highlighting: the row, column and box of your selected square light up, as do matching numbers.
Choose from four difficulties. The daily challenge gives everyone the same puzzle, so you can compare solve times with friends.
Sudoku at a glance
| Genre | Logic game |
|---|---|
| Price | Free, no download or sign-up |
| Controls | Tap, number pad |
| Typical game length | 5 to 30 minutes |
| Lives | 3 mistakes |
| Works on | Phones, tablets and computers, in any modern browser |
| Daily challenge | Yes, the same puzzle for everyone each day |
How to play Sudoku
- Select a square. Its row, column and box highlight.
- Tap a number. The number pad shows how many of each number are still needed.
- Use notes. Turn on Notes to pencil in small candidates.
- Solve the grid. Every row, column and box must contain 1 to 9 exactly once.
Rules
- A wrong number costs a heart; three mistakes end the puzzle.
- Hints fill in a correct square, costing a few points each (3 per puzzle).
- Placing a number automatically removes it from notes in the same row, column and box.
Levels and difficulty
Easy puzzles start with about 40 given numbers, Medium about 33, Hard about 28 and Expert about 24.
Scoring
Solving earns a base score by difficulty (from 1,000 on Easy to 5,000 on Expert), reduced by time and hints and increased for every heart left. Daily challenge scores can be shared with friends.
Tips and strategy for Sudoku
- Scan each number from 1 to 9 across all boxes to find squares where it can only go in one place.
- Look for "naked singles": squares where only one number is possible.
- Use notes on harder puzzles, and clear candidates as you place numbers.
- If a number can only go in one row of a box, it cannot appear in that row elsewhere.
History of the game
Modern Sudoku was first published in 1979 in Dell Magazines as "Number Place", created by American puzzle designer Howard Garns. The Japanese publisher Nikoli gave it the name Sudoku in the 1980s, and it became a worldwide craze in 2004 and 2005.
How we built and tested Sudoku
Every puzzle is checked by a solver to have exactly one solution before you see it. We generated puzzles at every difficulty and confirmed unique solutions each time; puzzles generate in a few milliseconds.
Frequently asked questions
Does every puzzle have one solution?
Yes. Each one is verified to have exactly one solution.
How do notes work?
Turn on Notes and tap numbers to pencil them into the selected square.
What happens after three mistakes?
The puzzle ends, and you score for the squares you filled.
Is there a daily Sudoku?
Yes. The daily challenge is the same puzzle for everyone each day.