SumSudoku: Killer Sudoku 4+

Crossovers with Kakuro flavor

Conceptis Ltd.

    • 4.8 • 463 Ratings
    • Free
    • Offers In-App Purchases



Play a crossover variation of Sudoku and Kakuro! SumSudoku, also known as Killer Sudoku, are addictive logic puzzles best described as a cross between Sudoku and Kakuro. Using pure logic and simple add/subtract calculations, these fascinating puzzles offer endless fun and intellectual entertainment to puzzle fans of all skills and ages.

Each puzzle consists of a 9x9 Sudoku grid containing areas surrounded by dark borders. The object is to fill all empty squares so that the numbers 1 to 9 appear exactly once in each row, column and 3x3 box, and the sum of the numbers in each area is equal to the clue in the area's top-left corner. In addition, no number may be used in the same area more than once.

The game includes helpful features such as showing possible sum number combinations in an area and pencilmarks to make temporary placement of numbers in the grid. To help see the puzzle progress, graphic previews in the puzzle list show the progress of all puzzles in a volume as they are being solved. A Gallery view option provides these previews in a larger format.

For more fun, Conceptis SumSudoku includes a Weekly Bonus section providing an extra free puzzle each week.


• 120 free SumSudoku puzzle samples
• Extra bonus puzzle published free each week
• Multiple difficulty levels from easy to very hard
• Puzzle library continuously updates with new content
• Manually selected, top quality puzzles
• Unique solution for each puzzle
• Hours of intellectual challenge and fun
• Sharpens logic and improves cognitive skills


• Unlimited check puzzle
• Unlimited hints
• Show conflicts during gameplay
• Unlimited Undo and Redo
• Show possible sum combinations option
• Pencilmarks feature for solving hard puzzles
• Autofill pencilmarks mode
• Highlight Excluded Squares option
• Lock number on keypad option
• Concurrently playing and saving multiple puzzles
• Puzzle filtering, sorting and archiving options
• Dark Mode support
• Graphic previews showing puzzles progress as they are being solved
• Portrait and landscape screen support (iPad only)
• Track puzzle solving times
• Backup & restore puzzle progress to iCloud


Conceptis SumSudoku have also become popular under other names such as Killer Sudoku, Sumdoku and Sumoku. All puzzles in this app are produced by Conceptis Ltd. - the leading supplier of logic puzzles to printed and electronic gaming media all over the world. On average, more than 20 million Conceptis puzzles are solved each day in newspapers, magazines, books and online as well as on smartphones and tablets across the world.

What’s New

Version 2.6

This version Introduces Dark Mode support: Enjoy a more comfortable viewing experience when solving puzzles in low-light environments

Ratings and Reviews

4.8 out of 5
463 Ratings

463 Ratings

17hope18 ,

Excellent game but please lower prices on additional puzzles

It would be nice for the weekly bonus puzzles to reflect the highest level of difficulty, or at least the 2 highest levels of difficulty the player is using.
If you increase the number of puzzles from 30 to 45 or even 50 for the $1.99 it would be great. This is a very good logic and strategy game that is very helpful to maintain brain health. It’s appropriate for all age groups. Please decrease the cost. I bet you would sell even more puzzles because we would not have to keep replaying the same games over many times. Do the math… evaluate the bottom line effect because money is tight for everyone. Please pay it forward. It’s a great game. The update you recently did adding the “hint” is excellent! Thank you!

Developer Response ,

Thank you for your interesting and original ideas! we will look into them and see how we can improve the pricing of our puzzles

porcupine888 ,

Great puzzles!

I have a lot of conceptis apps, and I always appreciate how many free puzzles they come with to get you started and how cheap buying additional puzzle packs is. SumSudoku is nice because the puzzles take a lot longer than many of the others - I might be able to do a Hard Nurikabe in 10-15 minutes but a few of the Easy SumSudokus take that long and many of the Hards take a half hour or more. The features included are super helpful - being able to put in number possibilities that automatically disappear when you put another number in, seeing all the instances of a certain number highlighted, etc.

Browser728008 ,

This is the best!

Some killer Sudoku apps will try to squeeze you for micropayments. And they have no features to let you choose how you want to play. They make things naturally difficult and make you “buy” undo and other helpful tools. But this one is honest. They sell you groups of puzzles if you want to buy them. And when you buy them, you really own them! You can reset them all and do them again later if you want. This app has great tools and they let you use them all or none. You choose how you play.

App Privacy

The developer, Conceptis Ltd., indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy.

Data Not Linked to You

The following data may be collected but it is not linked to your identity:

  • Identifiers
  • Usage Data

Privacy practices may vary, for example, based on the features you use or your age. Learn More


  • Family Sharing

    Some in‑app purchases, including subscriptions, may be shareable with your family group when Family Sharing is enabled.

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