Runs entirely in your browser - no upload, no sign-up.
Classic 9 x 9 puzzle
Enter the given digits, then solve the complete grid. Conflicting clues are highlighted as you type.
A Sudoku solver completes a standard 9 x 9 number puzzle so every row, column, and 3 x 3 box contains the digits 1 through 9 exactly once. Enter your starting clues and this browser tool checks them for conflicts, finds a valid solution, and marks solved cells separately from your original numbers.
Select each matching square and type a digit from 1 to 9, or tap a digit on the number pad. Leave unknown cells blank.
If a digit repeats in a row, column, or 3 x 3 box, the conflicting cells turn red. Correct them before solving.
Choose Solve puzzle. Your clues stay dark while the digits found by the solver use the accent color.
Copy the completed grid as nine text rows, or reset the board and enter another puzzle.
The solver works locally in your browser, so the puzzle is not uploaded and no account is needed. It uses constraint checking plus backtracking: it tries the cell with the fewest legal candidates first, which avoids much of the blind searching done by a simple left-to-right solver.
Duplicate digits are highlighted before solving. A puzzle can also be valid so far but impossible to finish; in that case, the grid stays unchanged and the status explains that no complete solution exists.
Yes. You can enter and solve as many standard 9 x 9 puzzles as you like without payment, registration, or a download. The example, conflict checker, full solver, mobile keypad, and copy function are all available for free.
No. The puzzle is checked and solved by JavaScript running in your browser. Your clues are not sent to a solving server, stored in an account, or included in the copied result unless you choose to paste that result somewhere else.
It solves classic 9 x 9 Sudoku puzzles that use digits 1 through 9 and the standard row, column, and 3 x 3 box rules. It does not support variants with cages, diagonals, irregular regions, extra symbols, or grids of another size.
The solver calculates the legal candidates for each blank cell, selects the blank with the fewest options, and tries those values in turn. If a choice creates a dead end, it backtracks and tries the next candidate until it finds a complete valid grid or proves none exists.
Red cells contain a repeated digit within the same row, column, or 3 x 3 box. Every cell involved in that conflict is highlighted, not just the most recently edited one. Change or erase one of the duplicates before pressing Solve puzzle.
Yes. A loosely constrained grid can allow several valid completions. A properly published Sudoku is normally designed to have exactly one solution. This tool finds a valid completion; it does not certify that the completion is unique.
Yes. Tap a cell and use the number pad below the grid, including the erase key. On a hardware keyboard you can type digits, use the arrow keys to move between cells, and press Backspace or Delete to clear the selected cell.
