How to play Sudoku

An unlimited Sudoku puzzle game. Choose your difficulty and play as many games as you like.

The objective

Fill the 9x9 grid with numbers so that each column, row, and 3x3 section contains all of the digits from 1 to 9 without repetition.

The rules

• 9x9 Grid — The board consists of nine 3x3 boxes (81 cells total).
• Rows & Columns — Each of the 9 rows and 9 columns must contain numbers 1 through 9 exactly once.
• 3x3 Boxes — Each of the nine 3x3 sub-grids must contain numbers 1 through 9 exactly once.
• Mistakes — You are allowed up to 3 mistakes per game before game over.
• Difficulty Levels — Choose from Easy, Medium, Hard, or Expert.

Features & controls

• Notes (Pencil marks) — Toggle notes mode to jot down candidate numbers in cells.
• Undo — Revert your last move.
• Erase — Clear a cell.
• Hint — Reveal the correct number for the selected cell (counts as a mistake).

Challenge your friends

When you complete a puzzle, share your time, difficulty, and score grid with friends via challenge links to see who solves it fastest!