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What the site offers
Play classic 9 × 9 Sudoku at four levels: easy, medium, hard and expert. Come back for the daily Sudoku, the same puzzle for every visitor on each date, or start younger players on 4 × 4 and 6 × 6 grids.
Beyond the game, you can print puzzle sheets with answer pages, check a puzzle from a newspaper or book with the Sudoku solver, and learn the techniques in how to play Sudoku and Sudoku tips and hints.
Who it is for
The site is built for anyone who enjoys a short, focused puzzle: complete beginners learning the three rules, regular players who want a fresh grid at their level, families looking for small grids, and people who prefer pencil and paper. Everything works on a phone, tablet or computer without an account or download.
How the puzzles are made
Every puzzle is generated by software, not copied from another publisher. Each one then passes two independent checks before it is published:
- A solution counter confirms that the puzzle has exactly one solution.
- A step-by-step logical solver finishes the puzzle using human techniques only, without guessing. The hardest technique it needed sets the level: singles for Easy, locked candidates for Medium, pairs and triples for Hard, and X-wing, swordfish or Y-wing for Expert.
- Puzzles the logical solver cannot finish are rejected rather than labelled.
Difficulty levels describe the techniques required, not the number of starting clues. Other publishers use their own scales, so an expert puzzle here may feel easier or harder than one elsewhere.
Editorial principles
- Accuracy first. Every technique explained in the guides is one the site's own solver uses, and the hint feature is tested to make sure each explained step places the correct number.
- No invented claims. We do not claim health, memory or brain-training benefits, expert endorsements or user statistics that we cannot support.
- Honest labels. Features are described as they are: puzzle types that are not playable here, such as killer or samurai Sudoku, are marked as not playable.
- Clear separation of paid content. Any sponsored article is labelled as sponsored, and its links are marked as such. The guidelines for sponsored articles are linked in the footer.
Reviews and corrections
Guides and page text are reviewed whenever the puzzle engine or a feature changes, and the date at the top of each information page shows its last update. If you find an error in a guide, a puzzle that seems wrong or a broken link, please tell us through the contact page. Confirmed errors are corrected.
Privacy by design
Games, settings and completion records stay in your browser's local storage on your own device. No analytics or advertising scripts are loaded. The contact form uses a necessary session cookie when delivery is enabled; fonts, images and scripts come from this server. Read the privacy policy and cookie policy for details.
Ownership and contact
Sudoku Puzzles Online is an independent website. The legal name of the operator has not yet been published on this site; you can ask for it, or raise any question about the site, through the contact page.
The puzzle collection behind the game
These counts come directly from the puzzle collections used by the game. They describe prepared puzzles, not visitors, downloads or an unlimited inventory.
| Collection | Prepared puzzles | Rating basis |
|---|---|---|
| Classic easy | 300 | Singles |
| Classic medium | 300 | Locked candidates |
| Classic hard | 250 | Pairs or triples |
| Classic expert | 200 | X-wing, swordfish or Y-wing |
| Kids 4 × 4 | 120 | Singles |
| Kids 6 × 6 | 200 | Singles |
Before deployment, every published puzzle is checked for one solution and solved with the logical techniques used for its stated level. The hint engine is also checked against the verified answer. These automated checks explain how the collection is tested; they do not imply hand-authored puzzles or an independent human review of every grid.