Question 1

How does a Killer Sudoku differ from regular Sudoku?

Accepted Answer

Killer Sudoku combines Sudoku with arithmetic. The grid is divided into cages — groups of cells that must sum to a given total. Like regular Sudoku, each row, column, and 3×3 box must contain the digits 1–9 exactly once. Unlike regular Sudoku, no starting digits are given — you deduce everything from the cage sums.

Question 2

How do I use this Killer Sudoku solver?

Accepted Answer

Click any cell to start building a cage, click adjacent cells to grow it, then enter the cage sum using the numpad. Repeat until all 81 cells are in cages. Click Check, then Solve to watch the solver work through every deduction step by step.

Question 3

What solving techniques does this tool use?

Accepted Answer

The solver uses cage elimination (ruling out digits that no valid combination supports), hidden singles (a digit that can only go in one place in a row, column or box), naked pairs, and backtracking for harder puzzles. Every step is explained in plain English.

Killer Sudoku Solver — Step-by-Step