400,000 puzzles.
Zero dead ends.
100,000 killer sudokus per difficulty. Each one is verified to have exactly one solution before it reaches your screen — so if you're stuck, it's solvable, promise.
Puzzle numbers are permanent: #4,821 on Hard is the same puzzle for everyone, forever. Send a friend the link and race them.
Your stats
| Difficulty | Solved | Best | Average |
|---|
Stats live in this browser only — no accounts, no servers.
Daily archive →Moving devices?
Copy a backup code here, then import it on your new phone or laptop to bring your streaks and stats with you.
Daily archive
Missed a day? It's still here. Streaks only count same-day solves, mind.
How to play killer sudoku
Killer sudoku is normal sudoku with one twist: there are no given digits to start from (mostly). Instead, the grid is carved into dashed cages, and each cage tells you what its digits add up to.
The rules
- Every row, column and 3×3 box contains the digits 1–9 exactly once.
- The digits inside each dashed cage add up to the small number in its corner.
- A digit can't repeat inside a cage.
Three tips to get you started
Where do 400,000 puzzles come from?
Every puzzle number is dealt deterministically from its number — the same number always produces the same puzzle, on any device. As it's dealt, a solver verifies the puzzle has exactly one solution before you see it. No broken puzzles, no ambiguous endings.
Controls
- Arrow keys move around the grid, 1–9 places a digit.
- Hold Shift with a digit (or toggle Notes) for pencil marks.
- Backspace erases, U undoes, N toggles note mode, Space pauses.
Go deeper
Three guides live alongside the game: a complete beginner's guide, the cage combinations cheat sheet (every sum, every cage size, forced combos highlighted), and the strategy guide covering the rule of 45, innies and outies.