How to Play Killer Sudoku - Rules & Tips
Cage sums on top of standard Sudoku—then use our player to drill row, column, and box logic.
100% free · No account or registration · Safe and fun for kids and families
Full Killer Sudoku partitions cells into disjoint cages with a target sum in each cage—digits inside a cage cannot repeat. Combined with standard Sudoku uniqueness per row, column, and 3×3 box, that pins placements more tightly than a plain grid. ProPuz’s in-browser game still renders a classic Sudoku board so you can practice the shared logic; read basic rules explained for the full picture and printables & how grids work for transparency.
The objective
Fill the 9×9 grid so that every row, every column, and every 3×3 box contains the digits 1 through 9, with no repeats.
Each row, column, and 3×3 box must contain 1–9 once.
Rules
- Each row must contain 1–9, without repetition.
- Each column must contain 1–9, without repetition.
- Each of the nine 3×3 boxes must contain 1–9, without repetition.
- Pre-filled cells (given at the start) cannot be changed.
Difficulty levels
Choose how many cells are already filled. Fewer givens means a harder puzzle.
Controls & actions
Click an empty cell to select it. Use the number pad or keyboard after selecting.
Press 1–9 to enter a number. Backspace or Delete to clear.
Turn on Notes mode, then tap a number to add or remove a candidate in the cell.
Clear the selected cell. Given numbers cannot be changed.
Revert your last move. Multiple undos are supported.
Reveal the correct number for the selected empty cell.
Stats
Shows how long you've been playing the current puzzle.
Wrong entries are counted. After 3 mistakes the game ends — start a new game to try again.