Do I need to download an app to play Sudoku?
No. SudokuStreak runs in your web browser - there is nothing to install, no app store and no store account. Open the page and the board is there. If you would rather it opened like an app, your browser can add it to your home screen; it still runs in the browser, and there is still nothing to download.
Can I play Sudoku online without signing up?
Yes. Every puzzle, every difficulty and the daily challenge are open without an account. Your game is saved in this browser as you play, and you get an anonymous name and avatar straight away. An account adds the leaderboard, coins and achievements, syncs your progress between devices and keeps it if you clear your browser - and the Sparks you earned anonymously come with you when you sign up.
Is it really free?
Yes. Every puzzle and every difficulty is free to play, and so is the daily challenge. You do not need a card and there is no trial that ends. Nothing on the site is behind a payment at all. There are no adverts on the site right now either.
What is the hardest Sudoku level I can play online here?
Evil, and it is checked rather than merely labelled. An Evil board starts with 23 of the 81 squares filled, and before it is dealt it has to be solvable with logic and to REQUIRE at least box/line elimination - if a board can be finished with simple scanning it is not dealt as Evil. Expert works the same way with pointing pairs. That matters because "Evil" is not a standard: on a site that only strips clues, a 23-clue board can still be a scan.
Does it have hints and pencil marks?
Yes, both. Notes mode lets you pencil small candidate digits into a cell while you work, exactly as you would on paper, and a hint fills in the correct value of the square you have selected. Free games come with a limited number of hints so the puzzle stays a puzzle. There is also a full-screen mode that puts the board and every control on one screen.
Is there a daily Sudoku and a streak?
Yes. One daily challenge a day, the same puzzle for everyone, in three difficulties - so your time is comparable with everybody else who played it. Finishing one keeps your streak alive; the streak is simply the number of days in a row you have solved the daily.
Which Sudoku variants can I play in the browser?
Center Dot Sudoku, Classic Sudoku, Dutch Whispers Sudoku, German Whispers Sudoku, Killer Sudoku, Mini Sudoku 4×4, Mini Sudoku 6×6, Nabner Sudoku, Samurai Sudoku, X-Sudoku - 10 types in all, and every one of them plays in the browser with no download. Each has its own rules page explaining what changes.
Does it work on a phone?
Yes. The board scales to the screen, works with touch, and has a layout for a phone held sideways that keeps the board and the number pad on screen together. Nothing to install here either.
Where to go next
- Play now - pick any of the 10 types and five difficulties.
- Evil Sudoku - what makes the hardest level hard, with the measurements behind it.
- Today's daily challenge - the same puzzle everyone else is solving.
- Sudoku School - the techniques, from singles to chains, so you never have to guess.
- Printable puzzles - if you would rather have it on paper after all.