P102KILLER SUDOKU CALCULATOR

Killer Sudoku Solver

Copy your puzzle in by drawing each cage and typing its total. The killer sudoku solver then works through it with you: ask for the next step and it points you to the right place, then reveals the digit and the reason. Or reveal the whole solution at once.

Tap the cells of one cage, or drag across them. Type the cage total and press Add cage. Repeat until every cell is in a cage. Tap a finished cage to change its total or delete it.

How to enter a puzzle

  1. In step 1, tap the cells of one cage, or drag across them.
  2. Type the number from the cage's corner into Total and press Add cage. The cage gets its dashed outline.
  3. Repeat for every cage. The line under the grid counts the cells covered and the totals so far, which add up to 405 in a complete grid.
  4. Switch to step 2 and press Next step whenever you are stuck.

You can type in digits you have already worked out on paper. They are checked against the solution before each hint, so a wrong digit is caught before it leads you astray.

How the hints work

Next step first tells you which technique to use and where to look, without giving the digit away. Press Reveal to see the cell, the digit and the full reasoning. The steps, simplest first:

One-cell cage
A cage with a single cell is simply its total.
Last cell in a cage
Once every other cell of a cage is known, the last one is what the total still needs.
Last cell in a row, column or box
The one digit still missing from it.
The 45 rule
Cages lying entirely inside a row, column or box (or two or three neighbouring rows or columns) leave the remaining cell to make up 45 for each of them. Cells sticking out of a house work the same way.
Only one digit fits
Everything else is already in the same row, column or box, or ruled out by the cage combinations.
Only one place for a digit
Within a row, column or box, a digit has just one cell left that can take it.
A digit the cage must contain
Every remaining combination for a cage uses a digit, and only one of its cells can hold it.

Stuck on a single cage rather than the whole grid? The killer sudoku calculator lists its combinations, and the combinations chart shows every cage at once.

Frequently asked questions

Why does it say the cages allow more than one solution?

Usually a total or a cage shape was entered differently from the puzzle. Check each cage against the printed grid. A genuine killer sudoku has exactly one solution.

What if a hint says one of my digits is wrong?

Before every hint the solver compares your digits with the solution, so it never builds on a mistake. Fix or erase the cells it lists, then ask again.

Why do some hints come straight from the solution?

The hints use the steps listed above. When none of them places a digit, the solver says so and reveals one cell from the solution instead of pretending there is a simple reason.

Is the example puzzle from a newspaper?

No. It was generated for this site and has exactly one solution.

Does it save my puzzle?

Yes, in your browser. Your cages and digits stay on this device until you clear them, and nothing is sent to a server.