Sudoku Solver

How to use the free Sudoku solver

Enter the given numbers from any standard 9x9 Sudoku puzzle directly into the grid, or paste an 81-character puzzle string using zeroes or full stops for empty cells. Check the puzzle first to catch conflicting clues, then choose Solve puzzle to complete the grid.

The solver is useful when you want to verify a puzzle, check a transcription or see the completed grid. It solves by calculation, so it gives the answer quickly. For a human-style explanation of the next logical move, use the Sudoku Coach instead.

What the solver checks

A valid Sudoku cannot repeat a number in any row, column or 3x3 box. The Check puzzle tool identifies invalid starting clues before solving. You can also export the completed board as an image, clear the grid and try another puzzle without leaving the page.

Sudoku solver FAQ

Is this Sudoku solver free?

Yes. You can enter, check and solve 9x9 Sudoku puzzles online for free.

Can I paste a Sudoku puzzle?

Yes. Paste exactly 81 characters, using the digits 1 to 9 for clues and either 0 or a full stop for each blank cell.