Frequently Asked Questions
Get answers to the most common questions about Sudoku and SudokuPuzzles.net
What are the basic Sudoku rules?
Fill each row, column, and 3×3 box with digits 1-9 without repetition. Each number can only appear once per row, column, and box.
Is guessing required to solve Sudoku?
No. All valid puzzles on our site are solvable by logic only. If you find yourself guessing, try looking for hidden singles, pairs, or other logical patterns.
What are the difficulty levels?
We offer 8 difficulty levels: Easy, Medium, Hard, Expert, Master, Extreme, Evil, and Insane. Extreme and Insane require unlocking by completing previous difficulty levels.
How do I unlock Extreme and Insane difficulties?
Extreme difficulty unlocks after completing 10 Expert puzzles. Insane difficulty unlocks after completing 10 Extreme puzzles. Your progress is tracked automatically.
Can I download puzzles to solve offline?
Yes! Visit our Download Puzzles page to get printable PDFs in all difficulty levels. Perfect for solving on paper or when you're offline.
Are there daily puzzles?
Yes! We offer a new daily puzzle every day. The difficulty rotates through all 8 levels, so you'll always have a fresh challenge.
What is the achievement system?
Our achievement system tracks your progress, including puzzle completions, streaks, and difficulty unlocks. View all achievements on the Achievements page.
Do I need to create an account?
No registration required! All features are available immediately. Your progress is saved locally in your browser.
How do hints work?
You get 3 hints per puzzle. Click the Hint button to reveal a correct number. Use them wisely!
What happens if I make too many mistakes?
You can make up to 3 mistakes per puzzle. After 3 mistakes, the game ends. You can start a new puzzle at any time.
Can I undo my moves?
Currently, you can clear a cell by selecting it and pressing Delete or Backspace. Full undo/redo functionality may be added in future updates.
Are the puzzles solvable?
Yes! All puzzles on our site have exactly one unique solution. They are generated using proven algorithms and verified for uniqueness.