Online Calcudoku Puzzles
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How to
How to solve

Early 2009, I read about KenKen (also known as Calcudoku) in the New York Times, and decided to write a program that creates similar puzzles, and put them online. Calcudoku puzzles are similar to Sudoku, but also require some basic math skills to solve.

The rules are:

  1. the 4×4 puzzle uses the numbers 1-4, the 6×6 the numbers 1-6, and so on
  2. in each row and in each column each digit can appear only once (just like in Sudoku)
  3. each "cage" (groups of cells with a thick border) shows a result and an operation (+ - × or :)
    The operation applied to the numbers in the cage should produce the result shown.
    Note that for subtraction and division the order is not fixed (!)

Check out this video that shows how to solve two example puzzles.

You can solve the puzzle on the page using the arrow and number keys, or using the mouse.
Other keys:

  • space bar : clear a cell
  • backspace : undo a move
  • = : highlight a number
  • Shift + number : enter the number as a guess

In the largest puzzles (10x10 Calcudoku puzzle (every Tuesday and Friday) and 12x12 (every Sunday and Thursday)), simply press 1 then 0, or 1 then 1, or 1 then 2 to enter 10, or 11, or 12. You can also use the a, b, and c keys to enter 10, 11, or 12.

You can also solve the puzzles on the iPhone/iPod Touch/iPad.

Every puzzle has a single solution.

This type of puzzle is known as Calcudoku, Newdoku, Rekendoku, MathDoku, Kashikoku-Naru, KenKen, Kendoku, Sumdoku, Calkuro, K-Doku, Keen, NekNek, CanCan, Square Wisdom, Emono, Minuplu, LatinCalc, Yukendo, ArithmeGrid, Hitoshii, Inky, SquareLogic, TomTom, and if you know of any other names, let me know :-). The "no-op" puzzles are sometimes called "Mystery Calcudoku". Of these names, "KenKen" and "KenDoku" are trademarks of Nextoy LLC. Note that this is a hobby site, and is not affiliated with Nextoy nor their brands.
Videos Forum Timed Rankings Books PDF Print 13 Oct 2026
Easy:
4×4
5×5
6×6
Killer
Sudoku
Medium:
4×4
6×6
8×8
Killer
Sudoku
Difficult:
4×4
6×6
8×8
9×9
Extra
Easy 4 × 4, Rating: 0  Points: 1     Solved 583 times
abcd
1 
3+
7+
1
3
Clear cell
Bold cell
Toggle pencil mode
Hide buttons
2 
 
 
7+
3+
3 
4
3+
 
 
4 
3
 
2
4
Undo
Start over
Change puzzle size
total
All puzzles published on this site are © Patrick Min. Send your ideas and suggestions to
Tomorrow's puzzles will appear in  hour(s) and  minute(s).