How to Play Killer Sudoku
Solve a Sudoku where groups of cells (cages) must sum to a given total, with no repeated digits allowed within any cage.
Try it now — Easy 9x9 →The Rules
- Standard Sudoku: each row, column, and 3×3 box contains digits 1–9 exactly once
- Cells within each dotted cage must sum to the cage's displayed total
- No digit may repeat within a single cage
- Cages never overlap each other
Available in 1 size (9x9) and 4 difficulty levels (easy, normal, hard, expert).
See It in Action
Standard Sudoku rules plus cells in each cage must sum to the cage total
How to Play
- List all valid digit combinations for each cage based on its sum and cell count
- Apply standard Sudoku elimination: digits placed in a row/column/box remove that digit from others in the line
- For 2-cell cages with extreme sums, the combination is unique — place those digits immediately
- Cross-reference cage possibilities with Sudoku constraints to pin down individual digits
Pro Tips
The "45 rule": any complete row, column, or box sums to 45 — use this to find the value of cells outside cages
A 2-cell cage summing to 3 must be {1,2}; summing to 17 must be {8,9} — memorize these unique pairs
Small cages with extreme sums have the fewest combinations — solve those first to anchor the rest
Frequently Asked Questions
What is Killer Sudoku?
Killer Sudoku combines Sudoku with Kakuro. The grid is divided into cages — groups of cells that must sum to a given number. Standard Sudoku rules apply, plus no digit may repeat within a cage.
Choose Your Challenge
Start with easy to learn the rules, then progress to harder difficulties.