Frequently Asked Questions

No - You can play as a guest at any difficulty from Easy to Extreme. However, creating a free account lets you save progress, view your personal stats, earn achievements, and compete in weekly competitions.

Progress is saved automatically every 30 seconds while you play (when signed in). You can also resume unfinished puzzles from your Dashboard → My Games. Guest sessions are not saved after closing your browser.

You have 3 allowed mistakes per puzzle. A mistake is counted when you enter a number that conflicts with the correct solution (it creates a duplicate in the same row, column, or box). At 3 mistakes the game ends. Using our notes mode helps avoid mistakes by tracking candidates.

Click the hint button (or press H) to reveal the correct number for one selected cell. Each hint reduces your final score. If you want to practice without hints, try our techniques guide to solve puzzles unaided.

Rankings in the Weekly Competition are based on: 1) valid completion, 2) highest score, 3) fastest time, 4) fewest hints, 5) fewest mistakes, 6) earliest submission time. All competitors solve the same puzzle.

Go to Sign In and click "Forgot password?". You'll receive an email with a reset link valid for 1 hour.

The leaderboard tracks scores from completed puzzles. There are all-time, weekly, and daily views. Competition entries have a separate ranked bracket on the competition results page.

Yes! Visit our Printable Sudoku page to generate and download puzzles at any difficulty level. Perfect for classrooms, travel, or offline play.

Enter any Sudoku puzzle into the Sudoku Solver and it will find the solution instantly using a backtracking algorithm. It's useful for checking your own solutions or analysing a puzzle you're stuck on.

If you're a registered user, open a support request from your Dashboard → Support for the fastest response. Otherwise contact us here. We respond within 24–48 hours.