Cosmic Sudoku — Free Online Space Sudoku Game
Cosmic Sudoku is a free, space-themed Sudoku game you play right in your browser. Solve 777 levels of classic 9×9 Sudoku as you travel from Earth to the edge of the universe, with a daily puzzle, streak tracking, and a lo-fi jazz soundtrack over an animated cosmos. No download and no sign-up — just open cosmicsudoku.com and play.
How to play
Fill every row, column, and 3×3 box with the digits 1–9 without repeating a number. Tap a cell and choose a number, use pencil/notes mode to jot candidates, and tap the hint button if you get stuck. Wrong entries are highlighted so you can correct them. Complete a level to unlock the next and beat your personal best time.
Features
- 777 levels of increasing difficulty, Easy to Hard.
- A new daily Sudoku puzzle — the same for every player.
- Streak tracking, full stats, and personal best times.
- Pencil/notes mode and 10 free hints per day.
- Animated space backgrounds, milestone cutscenes, and a lo-fi jazz soundtrack.
- Plays on desktop and mobile; add it to your home screen to play like an app.
Completely free
Every part of Cosmic Sudoku is free for everyone — all 777 levels, the daily puzzle, streaks, stats, and 10 hints per day, with no sign-up and no paywall. The game is supported by ads. If you'd like to support development you can buy me a coffee, but it is entirely optional.
Frequently asked questions
Is Cosmic Sudoku free?
Yes — completely free. All 777 levels, the daily puzzle, streaks, and 10 hints per day are free for everyone. The game is supported by ads and optional tips.
Do I need to download anything or sign up?
No. It runs entirely in your browser, with progress saved on your device.
How many levels are there?
777 levels, increasing in difficulty from Easy to Hard.
Is there a daily puzzle?
Yes — a new daily puzzle each day, identical for all players so you can compare times.
Does it work on mobile?
Yes. It's mobile-friendly and can be added to your phone's home screen.
More about Cosmic Sudoku
New to the puzzle? Read our how to play Sudoku guide, or sharpen up with Sudoku strategy and tips. You can also learn more about the game, or read our Privacy Policy, Terms of Use, and contact page.