Sudoku Solver
Solve any valid Sudoku puzzle instantly. Enter the 81 cells as a single string, row by row, and the solver fills in the rest using backtracking search.
Inputs explained
- Puzzle (81 digits, 0 or . for blanks) — All 81 cells reading left-to-right, top-to-bottom. Use digits 1-9 for clues and 0 or . for empty cells. Spaces and commas are ignored.
How to use it
- Fill in the fields above — each input has a hint describing exactly what to enter
- Press Calculate to get your result instantly, right on this page
- Copy the result, save the tool to favorites, or share and embed it anywhere
Understanding the result
Example: A puzzle whose first row reads 5,3,blank,blank,7... solves to 5 3 4 6 7 8 9 1 2 in row 1.
Frequently asked questions
What format should I use to enter the puzzle? Enter all 81 cells as a single string reading left to right, top to bottom, using 0 or a period for blank cells. No row breaks or separators are needed.
Will it solve any puzzle I type in, even an invalid one? No — the backtracking solver only returns a result for puzzles that have a valid, unique solution consistent with standard Sudoku rules. A puzzle with conflicting starting digits or no valid solution will fail to solve.
Is the Sudoku Solver free to use? Yes — it is completely free, with no sign-up, no download and no usage limits. You can use it as often as you need.
Is my data private? Yes. The calculation runs entirely in your browser — the values you enter are never sent to our servers, stored or shared with anyone.
What information do I need? Just the following: Puzzle (81 digits, 0 or . for blanks). Each field includes a hint explaining exactly what to enter.
Can I use it on my phone? Yes — the tool is fully responsive and works on any device, and the same calculator is available in the EasyWorkCalcs mobile app.
Privacy
Everything you enter into the Sudoku Solver is processed entirely in your browser. Nothing is uploaded, stored or shared — your data stays on your device.