Type in the digits of any sudoku. Next step shows the move a person would make, and why; Solve fills in the rest.
How does the sudoku solver work?
It fills the grid by the one rule of sudoku: every row, column and box holds each digit exactly once. It tries every possibility that rule allows, so it solves any valid puzzle, however hard.
Can it show me just the next step?
Yes. Next step places one digit and names the technique that proves it (a single, a hidden single, pointing, claiming or a naked pair), with the cells that make the case highlighted.
What if my sudoku has more than one solution?
The solver says so and shows one of them. A well-made sudoku has exactly one solution, so a second one usually means a digit was left out or typed wrong.
Does it solve 6×6 Mini Sudoku?
Yes. Switch the grid to Mini: six rows and six columns, boxes of two rows by three columns, digits 1 to 6.
What is a hidden single?
A digit that has only one possible cell left in a row, column or box. It must go there, even if that cell could still hold other digits.
Does the solver know today's puzzle?
No. It solves only the grid you type in; today's puzzles are on the Sudoku and Mini Sudoku pages.