Free online Sudoku
Play Sudoku the calm way, every single day
A fresh daily challenge, four difficulty levels, and smart logic-based hints in a clean, distraction-free board. No sign-up, no ads in your way, and it works offline.
No account required. Start solving in one tap.
Why players stay
Everything a great Sudoku game should be
Daily challenge
One shared puzzle every day with a rotating difficulty. Solve it fast and climb the daily leaderboard.
Logic-based hints
Stuck? Get a hint computed on your device using real Sudoku technique, naked and hidden singles. No AI, no guessing.
Global leaderboards
Ranked Classic games record your fastest times by difficulty, with fair server-side anti-cheat.
Four difficulties
Easy, Medium, Hard, and Expert, each with a hand-tuned number of givens for a fair, single-solution puzzle.
Plays offline
Puzzles generate locally, so a subway ride or a dead zone is no obstacle. Your streak is safe.
Light and dark
A refined board in both themes, with large tap targets and readable type that respects your font size.
New to Sudoku?
Learn to solve any puzzle
Our step-by-step guide covers the rules, pencil marks, and the core techniques that crack even Expert boards, with clear examples.
Read how to play- ✓The one rule that defines every Sudoku
- ✓Scanning rows, columns, and boxes
- ✓Naked singles and hidden singles
- ✓Using pencil marks to stay organized
Questions
Frequently asked
Is ZenSudoku free to play?+
Yes. Every puzzle, the daily challenge, and the leaderboards are free, and you can play without creating an account.
Do I need an internet connection?+
No. Puzzles are generated on your device, so you can play offline. A connection is only used to submit ranked times to the global leaderboard.
Does ZenSudoku use AI?+
No. Hints are computed by classic Sudoku logic (naked and hidden singles) directly on your device. There is no AI and nothing is sent to a server for a hint.
How does the daily challenge work?+
Everyone gets the same puzzle each day with a rotating difficulty. Solve it fast to climb the daily leaderboard and keep your streak going.
Ready for today's puzzle?
Jump straight into the daily challenge or pick your difficulty. It is free and takes one tap.
Play ZenSudoku