Sudoku Solver
Enter the numbers you know, click Solve, and get the answer instantly. Works for any valid 9x9 Sudoku puzzle.
How the Sudoku Solver Works
Our Sudoku solver uses a backtracking algorithm to find the solution to any valid 9x9 Sudoku puzzle. Enter the numbers you already know into the grid, click “Solve,” and the remaining cells will be filled instantly. The solver checks every row, column, and 3x3 box to ensure the solution follows standard Sudoku rules.
How to Use the Solver
- Click any cell in the grid and type a number from 1 to 9. Use Backspace or Delete to erase a number.
- Enter all the given (known) numbers from the puzzle you want to solve.
- Click the Solve button. If the puzzle is valid, the solution will appear in blue.
- Click Clear to reset the board and try another puzzle, or click Example to load a sample puzzle.
When to Use a Sudoku Solver
A solver is helpful when you are stuck on a particularly challenging puzzle, when you want to verify your own solution, or when you are learning new techniques by studying how the algorithm fills in cells. If you prefer to solve puzzles yourself, head over to our free online Sudoku game where you can play at six different difficulty levels with hints and error checking built in.
Improve Your Sudoku Skills
Want to solve puzzles on your own without the solver? Explore our learning resources and practice at every difficulty level: