Solve any Sudoku puzzle automatically or generate new ones to play. Easy, medium and hard difficulty levels.
What Is Sudoku Solver & Generator?
Sudoku is a logic-based number puzzle played on a 9×9 grid divided into nine 3×3 boxes. The objective is to fill every row, column and box with the digits 1–9, with each digit appearing exactly once in each row, column and box. No mathematics is involved — it is pure logical deduction.
This solver can help you with Sudoku puzzles in two ways: it can solve a puzzle completely so you can check your answer, and it can provide hints for specific cells when you are stuck. It uses efficient backtracking to solve any valid puzzle, and identifies "naked single" cells (where only one digit is logically possible) to give hints that feel like a real next step rather than just revealing the answer.
How to Use This Tool
Enter the given numbers in the puzzle grid (click a cell and type the digit).
Click "Solve" to see the complete solution.
Or click "Hint" to reveal the value of a single cell.
Use the timer to track how long you take on each puzzle.
Clear the grid to start a new puzzle.
Tips & Best Practices
Start by scanning for "naked singles" — cells where only one digit is possible given the row, column and box constraints.
Look for rows, columns or boxes where a digit can only go in one cell — this is the "hidden single" technique.
Use pencil marks (small candidate numbers) to track possibilities — this prevents mistakes in harder puzzles.
If you are stuck, look for pairs of cells in a row/column/box that share the same two candidates — you can eliminate those digits from other cells.
Common Use Cases
Checking your solution to a newspaper or book Sudoku puzzle.
Getting hints when stuck on a difficult puzzle without seeing the full solution.
Learning advanced Sudoku solving techniques by studying how the solver works.
Generating and solving puzzles for brain training and mental exercise.
Frequently Asked Questions
How does the solver work?
Enter the known numbers and click Solve. The algorithm uses backtracking to find the valid solution that satisfies all Sudoku rules.