SuuudokuuuFree, source-available, no ads
Play Free Online Sudoku
| c1 | c2 | c3 | c4 | c5 | c6 | c7 | c8 | c9 | |
|---|---|---|---|---|---|---|---|---|---|
| r1 | 2 | 3 | |||||||
| r2 | 6 | 5 | 8 | ||||||
| r3 | 7 | 6 | 2 | ||||||
| r4 | 5 | 8 | 9 | 7 | 4 | ||||
| r5 | 3 | 2 | 8 | ||||||
| r6 | 1 | 4 | 9 | ||||||
| r7 | 8 | 4 | 2 | 1 | 9 | ||||
| r8 | 3 | 4 | 7 | 1 | |||||
| r9 | 1 | 9 | 8 |
Free online sudoku means playing the classic 9×9 number puzzle in a browser or app with no purchase, install limit or paywall, and Suuudokuuu is a free, source-available implementation of it — seven difficulty levels from Newbie to Infinity, technique-explaining guides, no ads and no tracking in the game. Solve in the browser or install the app; your progress, streaks and stats stay on the device you play on. See why Suuudokuuu is built this way for the full, verifiable case.
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Why players stay
- Seven difficulty levels from Newbie through Hell to Infinity, the top tier serving record puzzles such as Everest and AI Escargot
- Technique-aware hints that name the exact solving pattern, not just the next digit
- Every puzzle guaranteed to have exactly one solution, and every tier below Infinity solvable without guessing
- No ads, no account and no tracking inside the game, on the web or in the app
- Works fully offline once installed on iOS or Android
- Shareable puzzle links and move-by-move replays of your recent games, the last 20 per difficulty
Learn to solve
Every technique Suuudokuuu uses to generate hints is documented with a worked example board pulled straight from the solving engine. Start with the full technique index, or jump into one of the first patterns most players learn.
- Full House — the simplest possible move, filling the last empty cell in a unit.
- Naked Single — a cell left with exactly one candidate.
- Hidden Single — a digit that only fits in one cell of a unit.
Stuck on a puzzle?
Type or paste the grid into the step-by-step sudoku solver and it will name every move — Hidden Single, Naked Pair, X-Wing — instead of just filling the board in. It checks that your puzzle has exactly one solution first, and it runs entirely in your browser.
New to Sudoku?
Read the how to play guide for the three rules and a walkthrough of your first moves, or look up any term in the sudoku glossary, which defines every technique and every piece of vocabulary the guides use.
Difficulty guides
Every tier from Newbie to Infinity now has its own guide, breaking down exactly what separates one level from the next — clue counts, required techniques and an honest read on how hard each one really is. Start on the Sudoku difficulty levels hub, or see how it compares to the hardest puzzles ever published.
Frequently asked questions
Is Suuudokuuu free?
Yes. Suuudokuuu is free and source-available, with no in-app purchases, subscriptions or paywalled difficulty levels.
Does Suuudokuuu have ads?
No. There are no ads anywhere and no tracking inside the game; this website uses only cookieless, anonymous page analytics.
Does it work offline?
Yes, in the iOS and Android apps. Once installed, Suuudokuuu generates and solves puzzles entirely on your device, so it plays the same with no connection.
What difficulty levels exist?
Seven: Newbie, Easy, Medium, Hard, Nightmare, Hell and Infinity. Hell puzzles come from a bundled, verified corpus of boards that each need a forcing chain, beyond anything Nightmare asks for, and Infinity serves record puzzles such as Everest and AI Escargot.