Sudoku Solver

Use this free sudoku solver to paste a puzzle or enter it cell by cell. It solves classic 9x9 sudoku directly in your browser, accepts dots or zeros for blank cells, and keeps your original givens visually separate from the generated solution.

How to use the solver

1. Click the first cell and type numbers, or paste the full puzzle into the grid.
2. When you paste, use . or 0 for empty cells.
3. Press Solve to complete the board and compare your givens with the solver-filled cells.

Accepted sudoku formats

• A single line with 81 characters.
• Nine lines with 9 characters each.
• Digits 1-9 for givens, plus . or 0 for blanks.

Why use an online sudoku solver?

A solver is useful when you want to check a printed puzzle, recover from a mistake, verify that a copied grid is valid, or study how close you were to the final answer. If you want to improve your own logic first, start with Sudoku for Beginners, review the Sudoku Rules, or practise on Easy Sudoku.

Frequently Asked Questions

What sudoku formats can I paste into the solver?

You can paste one line with 81 characters or nine lines with 9 characters. Empty cells can be written as dots or zeros.

Does the solver work in the browser?

Yes. The solving logic runs client-side in the browser, so you can solve puzzles without sending them to a server.

Can I type a sudoku cell by cell?

Yes. Click a cell and type a single digit. After each number, the focus moves to the next cell so you can fill the grid quickly.

Does the solver keep my original clues separate?

Yes. Your entered numbers stay visually distinct from the cells that the solver fills automatically.