Killer Sudoku
Sudoku with cages that must add up. 68 puzzles from Easy to Hard, each with exactly one solution, and a new daily puzzle. No ads, no sign-in.
Pick a square, then a digit. Cage digits add up to the small number.
Arrows move · 1–9 fill · 0 or Backspace clears · N toggles Notes.
How to play Killer Sudoku
Killer Sudoku keeps every rule of ordinary Sudoku — each row, column and 3×3 box holds the digits 1 to 9 once — and adds cages: dotted outlines around groups of squares, each with a small number in its corner. The digits in a cage must add up to that number, and a digit cannot repeat inside a cage. On the Hard puzzles no digits are given at all; the cage sums are the only clues.
Levels
- Easy — 24 puzzles with a few digits given to start you off.
- Medium — 20 puzzles with only four or five starting digits.
- Hard — 24 puzzles with no starting digits: pure killer.
- Daily — one puzzle a day from the whole collection, the same for everyone.
Every puzzle was checked by a solver to have exactly one solution, so each one can be finished by reasoning alone.
Techniques that help
- The 45 rule. Every row, column and box adds up to 45. If the cages inside a box add up to 41 except for one square sticking out, that square is 4.
- Unique sums. Some sums have only one set of digits: a two-square cage of 3 must be 1 and 2, of 17 must be 8 and 9; a three-square cage of 6 must be 1, 2 and 3.
- Pencil marks. Turn on Notes to jot down the digits a square could be, and clear them as you rule them out.
Frequently asked questions
Is Killer Sudoku free here?
Yes — all 68 puzzles and the daily puzzle play free in your browser with no ads, no sign-in, and nothing to install.
