Online Calcudoku Puzzles

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How to

Calcudoku

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:

the 4×4 puzzle uses the numbers 1-4, the 6×6 the numbers 1-6, and so on
in each row and in each column each digit can appear only once (just like in Sudoku)
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 Rankings Books Print

Today

Solution 3 Aug 2026

Easy:

4×4

5×5

6×6

Killer

Sudoku

Medium:

4×4

6×6

7×7

Sudoku

Difficult:

4×4

5×5

6×6

7×7

9×9

Extra

Difficult 7 × 7, Rating: ★★★★★ Solved 87 times

Today this puzzle is for subscribers only
(7 × 7, Difficult)

a b c d e f g

10-

6×

9×

10^

9×

4×

10 mod

6 mod

Note: this puzzle also uses the modulo operator mod
a mod b = r means that when dividing a by b, the remainder is r. For example, 5 mod 2 = 1, and 3 mod 5 = 3.
Look here for a longer explanation.

Note: this puzzle also uses the exponentiation operator ^
Example: 2^3 = 2 x 2 x 2 = 8
Or, with three digits: 2^4^2 = 2^(4^2) = 2^16 = 65536
Note: evaluation is right to left, and 0^0 = 1

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).Order puzzles

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