Sudoku Solver - Free Online Puzzle Solver
Find Sudoku solutions quickly and easily. Enter your puzzle, click Solve, and get the answer instantly. Our solver supports 6x6 Mini Sudoku, 9x9 Standard Sudoku, and challenging 12x12 puzzles.
How to Use the Sudoku Solver
Getting a solution is simple. Follow these three easy steps to solve any Sudoku puzzle.
Enter Your Puzzle
Click or tap on any cell to select it, then enter the numbers from your puzzle using the number pad or your keyboard. The solver will highlight conflicts in red if you enter duplicate numbers.
Choose Grid Size
Select the size that matches your puzzle: 6x6 for Mini Sudoku, 9x9 for Standard Sudoku, or 12x12 for larger puzzles. Switching sizes will clear your current input.
Click Solve
Press the Solve button and watch the solution appear instantly! If no solution exists, the solver will let you know so you can check your input for errors.
Keyboard Shortcuts
Enter number
Navigate cells
Clear cell
Undo
When to Use a Sudoku Solver
A Sudoku solver is a helpful tool for various situations. Here are some common use cases.
Stuck on a Puzzle?
We've all been there - staring at a puzzle for hours without making progress. Use the solver to get unstuck and continue enjoying your Sudoku journey.
Verify Your Solution
Finished a puzzle but not sure if it's correct? Enter your solution and let the solver verify it. A valid puzzle with your numbers filled in means you solved it correctly!
Learn Solving Techniques
Compare your progress with the solution to understand where you went wrong. This helps you learn new techniques and improve your solving skills over time.
Check Puzzle Validity
Creating your own puzzles or copying one from a book? Use the solver to check if the puzzle has a valid solution before sharing it with others.
Don't Spoil Your Fun
While our solver can instantly reveal the answer, remember that the real joy of Sudoku comes from the journey, not just the destination. The satisfaction of working through a puzzle, the "aha!" moments when pieces fall into place - these are experiences worth preserving.
Tips for Using the Solver Wisely
- Try solving on your own first - even if it takes a while
- Use the solver as a learning tool, not just an answer key
- Compare your partial solution to spot where you went wrong
- Challenge yourself with harder puzzles as your skills improve
Solver Features
Multiple Grid Sizes
Solve 6x6 Mini, 9x9 Standard, or 12x12 puzzles. Switch between sizes with a single click.
Conflict Highlighting
Instantly see when you enter duplicate numbers. Red highlighting shows conflicts in rows, columns, or boxes.
Instant Solutions
Our solver uses an efficient algorithm to find solutions in milliseconds, even for the most complex puzzles.
Easy Input
Click cells and use the number pad, or simply type with your keyboard. Navigate with arrow keys.
Dark Mode
Easy on your eyes with automatic dark mode support. Toggle between light and dark themes anytime.
Mobile Friendly
Works perfectly on any device - desktop, tablet, or smartphone. No app download required.
Frequently Asked Questions
How does the Sudoku solver work?
Our solver uses a backtracking algorithm - a powerful technique that systematically tries different number combinations while following Sudoku rules. When it hits a dead end, it backtracks and tries a different path. This method guarantees finding a solution if one exists, and it's fast enough to solve even the hardest puzzles instantly.
Can it solve any Sudoku puzzle?
Yes! Our solver can solve any valid Sudoku puzzle that has a solution. If your puzzle has multiple solutions (which happens when there aren't enough clues), the solver will find one of them. If the puzzle is invalid or has no solution, the solver will let you know.
What if no solution is found?
If the solver reports "No solution found," it usually means there's an error in your input. Double-check that you've entered the numbers correctly. The conflict highlighting feature will help you spot any duplicate numbers that violate Sudoku rules. Fix those errors and try again.
Is this Sudoku solver free?
Yes, completely free! No registration, no subscription, no hidden fees. Use it as many times as you want. We believe everyone should have access to helpful puzzle-solving tools.
What's the difference between 6x6, 9x9, and 12x12?
The numbers represent the grid size. 6x6 (Mini Sudoku) uses numbers 1-6 with 2x3 boxes - perfect for beginners. 9x9 (Standard Sudoku) is the classic format using numbers 1-9 with 3x3 boxes. 12x12 uses numbers 1-12 with 3x4 boxes - a bigger challenge for experienced solvers.