Support — Clean Modern Sudoku

Need help with Clean Modern Sudoku? Most questions are answered below. If not, contact us — details are at the bottom of this page.

How to play

• Fill the grid so every row, every column, and every 3×3 box contains the digits 1–9 with no repeats.
• Every puzzle has exactly one solution and is solvable by logic alone — you never have to guess.

Using the tools

• Notes (pencil marks): jot the candidate numbers for a cell while you work out the possibilities.
• Hints: stuck? A hint nudges you toward the next logical step.
• Undo: step back from a wrong turn.
• Mistake checking: catch slips early with gentle highlighting.

Saving & progress

• Auto-save: close the app any time — you’ll return to exactly where you left off.
• Timer & best times: track how long each puzzle takes and beat your personal best.

Frequently asked questions

How many puzzles are there?

300,000, across three difficulty levels (Easy, Medium, Hard) — you won’t run out.

Do I need an internet connection or an account?

No. Clean Modern Sudoku plays fully offline, with no account and no sign-up.

Can I change the theme?

Yes — switch between easy-on-the-eyes light and dark themes in Settings.

Is my progress backed up?

Your progress and best times are saved locally on your device. They aren’t synced across devices today.

Report a bug

Found something wrong? Contact us below. Telling us your device model, OS version, and what you were doing when it happened helps us fix it faster.