Play Killer Sudoku Online

For advanced solvers, Killer Sudoku combines classic Sudoku mechanics with arithmetic addition. While standard Sudoku requires purely logical placements, Killer Sudoku introduces an extra layer of math that makes it one of the most rewarding and challenging variations available.

Core Rules of Killer Sudoku

• Cages: The grid is divided into groups of cells outlined by dotted or dashed lines, called "cages."
• Target Sums: Each cage displays a small number in the top-left corner. The digits within that cage must sum up to exactly this target value.
• No Repetitions: No digit can be repeated inside a single cage.

Essential Killer Sudoku Strategies

1. Look for Unique Combinations

Some cage sums only have one possible combination of digits. For example, in a 2-cell cage:

• A sum of 3 must be [1, 2]
• A sum of 4 must be [1, 3] (cannot be [2, 2])
• A sum of 16 must be [7, 9]
• A sum of 17 must be [8, 9]

2. Master the "Rule of 45"

In standard Sudoku, the numbers 1 through 9 sum to exactly 45 (1+2+3+4+5+6+7+8+9 = 45). This means every row, column, and 3x3 box must sum to exactly 45.