Killer Sudoku Online

Killer Sudoku is the most popular sudoku variant — a 9×9 grid with no starting numbers, only dashed-outlined cages each carrying a target sum. The standard sudoku rules still apply (every row, column, and 3×3 box contains 1-9 exactly once), and Killer adds two: digits within a single cage must all be different, and the digits in a cage must add up to the cage's target sum. The result is a puzzle that demands both arithmetic and logical deduction. Sudoku247Online's Killer puzzles are freshly generated every play and uniquely solvable by pure logic. Start with Medium for a balanced challenge, drop to Easy to learn the variant, or push to Hard and Expert once you're confident with cage-combination tactics like the 45 rule and innies-and-outies.