Sudoku Solver
Solve any Sudoku instantly — paste or type the grid (dots or zeros for blanks) and get the completed solution, or learn that it has none or many.
How to use
- 1Type the puzzle row by row — 81 digits, using 0 or . for blanks. Spaces, bars and line breaks are ignored.
- 2The solved grid appears instantly.
How it's calculated
A backtracking search that always fills the cell with the fewest candidates first — it solves even the hardest valid puzzles in milliseconds.
Frequently asked questions
What if my puzzle has more than one solution?
You'll be told it has multiple solutions, and one of them is shown. A proper Sudoku has exactly one.
Why does it say the puzzle is invalid?
A digit repeats in a row, column or box — check for a typo in what you entered.
Can I enter it as one line?
Yes — 81 characters on one line work, as do 9 lines of 9.