Sudoku - How to Play & Solving Tips
The rules are simple: fill the 9x9 grid so every row, column, and 3x3 box contains the digits 1-9 exactly once. This free Sudoku game has four difficulty levels — Easy, Medium, Hard, and a genuinely tough Expert mode with only 20 starting clues and a verified unique solution, so it's a real step up once the lower difficulties feel too easy.
Use the Notes (pencil-mark) mode to jot down candidate numbers in a cell before committing, and let conflict highlighting flag any row/column/box clash instantly so mistakes get caught early instead of unraveling the whole grid later. A built-in timer and best-time tracker make it easy to see yourself improving across sessions.
Play Sudoku online free with no download and no sign-up — pick your difficulty and start solving, whether you're working through Easy puzzles for a quick break or grinding Expert for a real logic challenge.
How to Play Sudoku: Step by Step
- Choose Easy, Medium, Hard or Expert.
- Tap an empty cell, then choose a number from 1 to 9.
- Each row, column and 3x3 box must contain 1 to 9 exactly once.
- Turn on Notes to write small candidate numbers in a cell.
- Clashes are highlighted, so you can fix mistakes right away.
Sudoku Tips for Beginners
- Start with the number that already appears most often on the grid.
- Scan each 3x3 box to see where a missing number can go.
- Look for cells with only one possible number.
- Use Notes on harder puzzles instead of guessing.
- If two cells in a row can only hold the same two numbers, remove those numbers from the rest of that row.
Sudoku FAQ
Which level should I start with?
Start with Easy. Move up when you finish without mistakes.
How hard is Expert?
Expert starts with only 20 clues and always has one unique solution.
Does it track my time?
Yes. There is a timer and a best-time record.
Want to improve faster? Read our Sudoku strategy guide, or see all 16 free games.