Sudoku solver
Stuck on a Sudoku? Do it in two steps. First type in the numbers that are printed in your puzzle. Then choose how much help you would like, from a single hint to the whole answer.
1Type in the numbers from your puzzle
The number pad types:
No puzzle to hand?
2Choose the help you want
These buttons open when you have typed at least 17 numbers from your puzzle. A Sudoku needs at least 17 numbers to have only one answer.
Fill in squares
Fill one part of the grid
Tap a square in the grid first, then choose what to fill.
Understand the puzzle
Check your work
Tidy up
Show the reason for each filled number
How the solver works
The solver first uses the same steps a careful person would use. A square with only one number that fits is filled in, and so is a number that has only one place left in its row, column or box. When no step like that is left, the solver works out the full answer and uses it, and the reason says so. The answer is always checked: if your numbers clash, or no solution exists, you are told before anything is filled in. Your guesses are never used to work out the answer, so a wrong guess cannot spoil it.
How the Sudoku solver helps you
Type the numbers from your puzzle into the grid, then choose how much help you want. You can ask for one square, the next two, about half of the empty squares, or the whole answer. You can also fill only one row, one column, one box, or every place a chosen number belongs. If you only want to understand the puzzle, ask for a hint that explains the reasoning, switch on pencil notes, or ask how hard the puzzle is.
Questions about the Sudoku solver
Can it solve any Sudoku puzzle?
It solves any valid puzzle. If the numbers you entered clash, or the puzzle has more than one answer, the solver says so instead of guessing.
Will it explain how to get the next number?
Yes. A hint names the square and the reasoning, such as the only number that fits or the only square in a box where a number can go. That lets you learn the technique and then continue by yourself.
How does it rate a puzzle?
A puzzle is Easy when it can be solved with only squares that have one possible number. It is Medium when it also needs squares where a number has only one place in a row, column or box. Anything that needs more than that is Hard.
Can I make my own puzzle?
Yes. The puzzle maker builds a fresh puzzle with exactly one answer at the level you pick. You can also play a full game on the Sudoku page.
To learn the techniques the solver uses, read Sudoku techniques for beginners.