Killer sudoku
Free killer sudoku, online and printable. No sign-up, no ads, no watermark. Play a new puzzle every day, or print up to 20 at easy, medium or hard, with a PDF answer key on US Letter or A4.
On a keyboard: arrows move, 1 to 9 fill in, Delete erases, N turns notes on and off.
Printable killer sudoku
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The preview redraws as you go. This is exactly the page that prints.
Killer sudoku is sudoku with no starting numbers: dashed cages show what their squares add up to, and you fill the grid from those totals. Play today's free puzzle in your browser, or print sheets from easy to hard. Every puzzle has one answer you can reach by logic alone.
Updated
How to solve a killer sudoku
- Write a digit from 1 to 9 in every square, so each row, each column and each 3 x 3 box holds every digit once.
- Dashed outlines split the grid into cages. The small number in a cage's corner is the total of its squares.
- No digit repeats inside a cage.
Start with the cages that allow only one set of digits. Two squares totalling 3 must be 1 and 2. Two totalling 17 must be 8 and 9. Three totalling 6 must be 1, 2 and 3; three totalling 24 must be 7, 8 and 9.
Then use the 45 rule. The digits 1 to 9 add up to 45, so every row, column and box totals 45. If the cages inside a box cover all but one square and add up to 38, that last square is 7. It works on rows and columns too, and it's the most useful move in the game.
Today's killer sudoku
A new puzzle every day, the same for everyone on the same date. It changes at midnight where you are. Easy on Monday and Tuesday, medium Wednesday to Friday, hard at the weekend.
- Tap a square, then a digit on the keypad. Erase clears it.
- Notes puts small pencil marks in a square instead, for the digits you're still deciding between.
- On a keyboard: arrows move, 1 to 9 fill in, Delete erases, N turns notes on and off.
- Check shows wrong squares in red and tells you how many are left.
- Play another gives you a new puzzle at the level you pick.
Your progress saves in this browser, so you can come back to it. It stays on your device; see Privacy.
Printable killer sudoku
Pick easy, medium or hard, then print up to 20 puzzles at a time, one, two or four to a page, with the answers at the back. One to a page gives the biggest grid and room for pencil notes. Untick Print the answers to print the puzzles alone.
Killer sudoku: questions
Is it free?
Yes. The daily puzzle and the printables are free, with no account and no ads.
Do I need to be good at math?
No. It's addition you can do in your head. The challenge is the logic.
Is killer sudoku the same as sum sudoku or sumdoku?
Yes, those are other names for it.
Does every puzzle have one answer?
Yes. Each one has exactly one solution and can be solved without guessing. A separate checker confirms it before the puzzle is shown.
Can I sell puzzles I make here?
Yes. Use them for anything: classrooms, newsletters, party games, or your own puzzle books for sale. You don't need to ask or pay. Free sheets keep one small line at the bottom of each page with our name and web address. A Pro version, coming later, will make sheets without that line and export a whole book at once.