Frequently asked questions
Is Sudoku·AD free?
Yes. Every puzzle, lesson and tool is free to use. There are no ads, no tracking scripts and nothing to buy. Details are in the privacy policy.
Do I need an account?
No. You can play, use the lessons and make puzzles without signing up, and your progress stays on your device. A free account keeps your streak on every device.
Which kinds of sudoku can I play?
Classic sudoku and 41 variant rule types, including killer, thermometer, arrow, Kropki, German whispers, renban, XV, sandwich and fog of war. Every variant has its own page with the rule and puzzles to play: see all variants.
What is in the puzzle library?
The puzzle library is hand-picked classic and variant puzzles, and setters who want theirs here can send them to hello@sudoku.ad. On top of that you can start an unlimited number of generated puzzles for any variant at four difficulties.
Where do the puzzles come from, and who made them?
Library puzzles are either made by the site or shared by their setters. Each one is credited to its setter by name, with a link to the original publication where there is one: puzzles by setter. Generated puzzles are made by the site and have a unique solution.
I am a setter. How do I have my puzzles removed or my credit corrected?
Ask on the for setters page or write to support@sudoku.ad. You can keep all, some or none of your puzzles on the site, and a removal or a credit correction (a wrong name, a missing co-setter, a bad link) is made on request. Nothing is sold or rebranded.
Can I play a puzzle from another site?
Yes. Paste its link from any puzzle site or player, or an f-puzzles or Penpa+ link, into the box on the home page or the + at the top of any page. It is added to your private library and ready to play, with no sign-up needed. It stays private to you, it is credited to its setter, and it links back to the original.
Can I make my own sudoku?
Yes. The Create editor lets you build a classic or variant sudoku by hand, checks that it has exactly one solution, and gives you a link to share it.
Is there a daily puzzle?
Yes. A new sudoku every day, the same board for everyone, so you can compare your time with other players. See the daily puzzle. There is also a featured puzzle each week in the weekly contest.
Does it work on a phone, and offline?
Yes. Sudoku·AD runs in any modern browser on a phone, tablet or computer, and it can be installed to your home screen like an app. Once it has loaded, the daily puzzle and puzzles you have already opened keep working without a connection.
Is there Calcudoku?
Yes. Calcudoku is the number puzzle where the digits in each cage must reach the clue with + − × or ÷. Grids run from 4×4 to 9×9 at four difficulties, and every puzzle has one solution.
How can I learn the solving techniques?
Use Learn for interactive lessons that teach each technique and each variant rule on a real board, or read the solving guides. In a puzzle, the hint button explains the next step instead of only showing it.
More about the site: About Sudoku·AD.