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Play Sudoku Online Free
Challenge your brain with beautifully designed Sudoku puzzles — from beginner-friendly boards to expert-level logic battles. Instant play in your browser on any device.
2.4M+
Puzzles Played Daily
∞
Unique Puzzles
3
Difficulty Levels
100%
Free, Forever
Difficulty Levels
Pick Your Challenge
Every puzzle is algorithmically guaranteed to have exactly one valid solution — no guessing required.
E

Easy Mode

Perfect for beginners. More starting numbers, simple scanning and cross-hatching techniques.

Beginner
M

Medium Mode

Ready for a challenge? Use hidden singles, candidate elimination and pencil notes.

Intermediate
H

Hard Mode

Requires Naked Pairs, Pointing Pairs, X-Wing and Swordfish logic strategies.

Expert
Daily Challenge
Build Your Streak
A fresh puzzle every day. Complete it to extend your monthly streak.
Premium Features
Everything You Need
No account. No ads interrupting your flow. Just pure logic puzzles.
⚡

Instant Browser Gameplay

Lightweight HTML5 and JavaScript for lag-free play on any device, desktop to mobile.

💾

Auto-Save Progress

Your board, timer, notes and difficulty settings persist automatically — continue anytime.

✏️

Pencil Notes Mode

Mark candidate numbers in cells digitally. Solve complex boards without pen and paper.

❌

Smart Conflict Detection

Duplicate numbers are instantly highlighted so you catch mistakes before they compound.

🔍

Number Highlighting

Tap any digit to highlight all matching numbers across the board for faster scanning.

🌙

Dark Mode & Themes

Classic light, OLED dark, and high contrast modes for comfortable play in any environment.

Advanced Techniques
Master the Logic
Sharpen your solving with these expert strategies used by Sudoku champions worldwide.
Naked Pairs
Hidden Pairs
Pointing Triples
X-Wing
Swordfish
Coloring
Forcing Chains
Hidden Singles
Box-Line Reduction
💡

Pro Tip

Never guess. If you're stuck, activate Pencil Notes and use the Hint feature to logically narrow down possibilities. Every Sudoku puzzle generated here can be solved through pure reasoning alone — no guessing required.

FAQ
Common Questions
Fill every row, column, and 3×3 box with the numbers 1 through 9 without repeating any number. Use logic and deduction to determine correct placements — no math required.
Yes — completely free with no account, no download, and no subscription. Play unlimited puzzles at any difficulty, any time.
Absolutely. The game is fully optimized for Android and iPhone with responsive touch controls, a mobile number pad, and smooth animations.
Sudoku regularly exercises concentration, pattern recognition, logical reasoning, and working memory. Daily play can help maintain and sharpen cognitive focus over time.
X-Wing, Swordfish, and Forcing Chains are considered among the most difficult solving methods. They require reasoning across multiple rows and columns simultaneously to eliminate candidates.