How to Play Sudoku

Fill the Grid

Fill the 9×9 grid so each row, column, and 3×3 box contains the numbers 1 through 9 exactly once. Some numbers are pre-filled as clues.

Use Logic, Not Guessing

Every Sudoku puzzle has exactly one solution. Use logical deduction — never guess. Our Smart Hints teach you proven solving techniques.

Notes Mode

Toggle Notes mode to add small candidate numbers to cells. This helps track possibilities and is essential for harder puzzles.

Six Difficulty Levels

Start with Easy (36+ clues) and work up to Extreme (21 clues). Each level requires more advanced solving techniques.

Keyboard Shortcuts

Use arrow keys to navigate, 1-9 to fill numbers, Ctrl+Z to undo, H for hint, N for notes. Full keyboard support for power users.

Track Your Progress

Timer, mistake counter, and completion percentage keep you informed. Your game auto-saves — pick up right where you left off.

Play Free Sudoku Online

Sudoku is one of the world's most popular puzzle games. The goal is simple: fill a 9×9 grid so each row, column, and 3×3 box contains the digits 1-9. But the challenge grows with every empty cell — a well-crafted Sudoku puzzle is a workout for your logical reasoning skills.

Puzzles-Sudoku offers six difficulty levels — from Easy (perfect for beginners) to Extreme (a true test for experts). Our Smart Hints don't just give you the answer; they teach you how to find it yourself, one solving technique at a time.

Why Play Sudoku Online?

Online Sudoku has key advantages over paper puzzles: smart hints, auto-saving progress, mistake detection, notes mode, and unlimited puzzles. No erasing, no restarting — just pure puzzle-solving flow.

Learn more in our complete Sudoku rules guide and explore our solving techniques library.