Killer Sudoku
Cages must sum to the given total — no digit repeats within a cage
Killer Sudoku is fully playable. Choose a difficulty and start solving.
Killer Sudoku overlays cages on the standard 9×9 grid. Each cage is a group of cells outlined by a dashed border, with a small number in the corner showing the sum of all digits in that cage. Digits may not repeat within a cage. No standard given digits appear in the grid — all clues come from the cage sums. Killer Sudoku requires both Sudoku logic and arithmetic reasoning, making it one of the most popular and challenging Sudoku variants.
Like all Sudoku variants, Killer Sudoku builds on the classic 9×9 foundation. Every row, column, and 3×3 box must contain each digit from 1 to 9 exactly once. The variant constraint is added on top of these standard rules, never replacing them.
If you're new to Sudoku, start by learning the basic rules and techniques before attempting variants.
Techniques Useful for This Variant
| Technique | How it applies |
|---|---|
| Pencil Marks / Notes | Essential for tracking candidates alongside the variant constraint |
| Obvious Singles | Cells narrowed to one candidate by the combined constraints |
| Hidden Singles | Digits with only one valid cell in a unit after variant elimination |
| Pairs and Triples | Locked candidates exposed by the additional constraint |