Daily Killer SudokuHard

Friday, July 3, 2026
Best Time --:--Next puzzle in
Time00:00
Mistakes0/3
Hints3
1Fill the grid so each row, column, and 3×3 box contains 1-9
2Each dashed cage must sum to the number shown in its corner
3Numbers must not repeat within any cage
4Use cages and sums to deduce which numbers go where
1-9 1-9: Place number in selected cell
Backspace/Delete: Erase selected cell
Ctrl+Z Ctrl+Z: Undo last move

What is Killer Sudoku?

Killer Sudoku combines the rules of classic Sudoku with cage sum constraints. The 9×9 grid is divided into cages — groups of cells outlined with dashed borders — each labeled with a target sum. Your goal is to fill every cell so that each row, column, 3×3 box, and cage satisfies its constraints.

No initial clues are given. Instead, you deduce each number using cage sums and the rule that digits cannot repeat within a cage. It's pure logic from start to finish — a deeper challenge than classic Sudoku.

Why Play Killer Sudoku?

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Pure Logic

No given numbers — every digit is deduced through cage sums and elimination. The ultimate logic puzzle.

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Daily Challenge

A new Killer Sudoku puzzle every day at midnight UTC. Same puzzle for all players worldwide.

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Streak & Stats

Track your daily streak, best time, and completion rate across all difficulty levels.

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Full Archive

Play any past date. Practice on easy days or push yourself on expert-level cages.

Instant Play

No sign-up, no ads. Open your browser and start solving immediately.

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Works Everywhere

Fully responsive — play comfortably on desktop, tablet, or phone.

Killer Sudoku Tips

The 45 Rule: each row, column, and 3×3 box must sum to 45 (1+2+…+9). Use this to narrow down cages.
Learn common cage combinations: a 2-cell cage summing to 3 can only be {1,2}; summing to 17 can only be {8,9}.
Start with small cages (1–2 cells) and cages with unique combinations — they give you the most information.
Use cage elimination: if a cage must contain certain digits, those digits cannot appear elsewhere in the same row/col/box.
Look for hidden singles within cages — sometimes only one cell can hold a particular digit.
Pencil marks are essential in Killer Sudoku. Use notes mode liberally to track candidates.
Check cage sums as you fill cells — if a cage's filled cells already reach the target, the remaining cells must account for the difference.

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New puzzle daily at midnight UTC. All progress saved locally. No data collected.