Daily Killer Sudoku

What is the Daily Killer Sudoku?

The Daily Killer Sudoku is a fresh 9×9 puzzle published every day at midnight UTC. Each puzzle is uniquely numbered from launch, creating a persistent timeline you can track and share.

Your streak counter tracks consecutive days completed. Unlike practice mode, each daily is a shared experience—everyone worldwide solves the same puzzle on the same day.

Difficulty by Weekday

Daily Killer Sudoku follows a predictable difficulty curve throughout the week, ramping up from Monday to Saturday, then resetting for Sunday:

This curve gives beginners reliable easy days while challenging experienced solvers at week's end. If you miss a day, you can always go back—dailies remain playable forever.

How to Play

Fill the 9×9 grid so each row, column, and 3×3 box contains all digits 1-9 without repetition. Unlike classic Sudoku, there are no given digits. Instead, the grid is divided into cages (groups of cells with dashed borders).

Each cage has a small number in the top-left corner showing the target sum. All digits within a cage must be different and must add up to that sum. For example, a 2-cell cage with sum 7 could be {1,6} or {2,5} or {3,4}.

Start with small cages where only one combination is possible. For example, a 2-cell cage with sum 3 must be {1,2}. Use Notes Mode to track candidate digits for each cell. Look for cages that overlap in the same row, column, or box—these create powerful elimination opportunities.

The Check button highlights conflicts in both standard Sudoku rules and cage constraints. Your timer pauses when you switch tabs. Progress saves locally using IndexedDB—no account needed.

For detailed rules, cage strategies, and common sum combinations, visit the Killer Sudoku hub page.