Calcudoku Solver — Step-by-Step Solution with Board Builder

Calcudoku Solver: rules, how to use it, tips

Fill an N×N grid with 1 to N — no repeats in a row or column — so every cage hits its target using its operation.

An N×N grid uses the digits 1 to N. Each row and each column contains each digit exactly once.
Bold outlines group the cells into cages. Each cage shows a target and an operation: + − × or ÷.
The digits in a cage must make the target with that operation. For − and ÷ the cage has two cells, and you take the larger number first (6 − 2 = 4, 6 ÷ 2 = 3).
A one-cell cage simply gives you the digit.
A digit may repeat inside a cage, as long as the copies are not in the same row or column (possible only in L-shaped or larger cages).

① Build puzzle: choose the grid size, select cells to make a cage, then set its operation and target.
② Check: the solver checks every cell is caged and the puzzle can be solved.
③ Solve: watch it solve cage by cage, with every deduction explained.
Load the sample puzzle to try it first.

Fill the freebies. One-cell cages are given digits. Write them in first.
List the few options. A two-cell 3− cage in a 4×4 can only be 1 and 4. A 2÷ cage is 1&2, 2&4 or 3&6 depending on the grid size.
Use large products. Multiplication cages with big targets have few factorisations — 60× in three cells of a 5×5 must be 3, 4 and 5.
Row and column totals. Every row adds up to 1+2+…+N. On a 6×6 that is 21, so cages that share a row tell you about the leftover cells.

The full guide, with a worked example and common mistakes: How to play Calcudoku.

Are Calcudoku, Mathdoku and KenDoku the same puzzle?

Yes — the same rules under different names. This site has a cage calculator under each name: Calcudoku, Mathdoku and KenDoku.

Which number comes first in a − or ÷ cage?

The larger. A 2÷ cage of 3 and 6 means 6 ÷ 3.

Can digits repeat inside a cage?

Only when the cage is bent so the repeated digits sit in different rows and different columns.

What is Operators Hidden mode?

A harder mode in the Calcudoku game where cages show only the target — you deduce the operation as well as the digits.

How do I see every combination for a cage?

Enter the grid size, operation, cells and target in the cage calculator, or browse the cage combinations tables.