Choose Difficulty
Controls: Click cells to select, use number keys (1-9) or number pad to fill, Backspace/Delete to clear, N for notes mode.
What is Sudoku?
Sudoku is a classic logic-based number placement puzzle that challenges your problem-solving skills. The objective is to fill a 9×9 grid with digits 1-9 so that each column, each row, and each of the nine 3×3 sub-boxes contains all digits from 1 to 9 without repetition. Unlike word puzzles or trivia games, Sudoku relies purely on logical deduction and pattern recognition. Every puzzle has exactly one unique solution, making it a perfect brain training exercise that improves concentration, memory, and analytical thinking.
Who is Sudoku Good For?
Sudoku is perfect for anyone looking to exercise their brain and improve logical thinking skills. It's ideal for students who want to enhance their problem-solving abilities, adults seeking a mental workout during breaks, seniors maintaining cognitive health, and puzzle enthusiasts who enjoy challenging logic games. With three difficulty levels (Easy, Medium, Hard), Sudoku adapts to all skill levels—from beginners learning the basics to experts tackling complex puzzles. It's also great for kids (ages 8+) as an educational tool that teaches patience, focus, and systematic thinking.
Why Play Sudoku Online for Free?
Our free online Sudoku game offers several advantages over printed puzzles or paid apps. You get instant access to unlimited puzzles without downloading anything or creating an account. The game provides helpful features like error highlighting, notes mode for candidates, and automatic validation—tools that help you learn and improve faster than traditional paper puzzles. You can play on any device (phone, tablet, computer) anywhere, anytime. Plus, with three difficulty levels and randomly generated puzzles, you'll never run out of challenges. It's completely free with no ads interrupting your solving experience.
How to Play
Sudoku is a logic-based number placement puzzle. The objective is to fill a 9x9 grid with digits 1-9 so that each column, each row, and each of the nine 3x3 sub-boxes contains all digits from 1 to 9 without repetition. Use logic and deduction to find the correct placement for each number. The puzzle has a unique solution.
Controls
- Click a cell to select it
- Use number keys 1-9 or tap number pad
- Arrow keys to navigate cells
- Press N to toggle notes mode
- Backspace or X to clear a cell
Features
- • Three difficulty levels
- • Each puzzle has unique solution
- • Error highlighting
- • Notes mode for candidates
- • Cell highlighting
- • Mobile-friendly controls
- • No registration required
Frequently Asked Questions
What is Sudoku?
Sudoku is a logic puzzle where you fill a 9x9 grid with numbers 1-9, ensuring no repetition in rows, columns, or 3x3 boxes.
How do I solve Sudoku?
Look for cells where only one number is possible. Use elimination to find where numbers must go based on existing placements.
Is every puzzle solvable?
Yes, every puzzle generated has exactly one unique solution.
What are notes for?
Notes let you mark possible candidates for a cell before committing to an answer.
Is this free to play?
Yes, completely free. No download or registration required.
Can I play on mobile?
Yes, Sudoku is fully responsive and works on all devices.