How do you play Sudoku?
Fill a 9×9 grid so every row, column, and 3×3 box contains each digit from 1 to 9 exactly once.
How to Play Sudoku
Learn the classic Sudoku rules for rows, columns, and 3×3 boxes before you start solving free online puzzles.
Classic Sudoku
1
The Grid Structure
The board is a 9×9 grid divided into nine 3×3 blocks (regions).
2
The Goal
Fill every empty cell with digits 1–9. You start from a partially completed puzzle with one unique solution.
3
The Golden Rule
Digits 1–9 cannot repeat in any row, column, or 3×3 block — each must appear exactly once.
Killer Sudoku
Killer Sudoku adds cage sums to classic Sudoku rules. Use the dedicated guide for cages, no-repeat cage rules, and beginner strategies.
Learn Killer Sudoku rulesSudoku FAQ
What is the difference between easy and hard Sudoku?
Easy Sudoku puzzles start with more given digits and leave fewer cells to solve. Hard puzzles have fewer clues and usually require more advanced deduction.