sudoku online - Play Free Sudoku Puzzles Online Every Day
sudoku online brings you unlimited free number puzzles to sharpen your mind every day. Choose from easy, medium, hard, and expert difficulty levels, use hints when stuck, and track your progress as you master the world's favorite logic game.
βΈ How to Play sudoku online
- Pick a difficulty β Easy, Medium, Hard, or Expert. A fresh 9Γ9 puzzle grid loads with some numbers already filled in as clues.
- Click any empty cell and type a digit from 1 to 9. Each number can only appear once per row, once per column, and once per 3Γ3 box.
- Stuck? Tap the Hint button to reveal the next logical move. It shows which cell to solve and explains the reasoning, so you learn as you play.
- Use pencil marks (small candidate numbers) to track possibilities in each cell. Toggle Auto-Note to fill candidates automatically for every empty cell.
- Complete the grid so every row, column, and 3Γ3 box contains digits 1 through 9 with no repeats. Check the timer to track your personal best!
β¦ Why Players Love sudoku online
Endless Puzzles Across Four Levels
Jump into easy mode for a relaxing warm-up or challenge yourself with expert-grade grids. New puzzles generated daily so you never run out of fresh number-logic challenges.
Smart Hint System That Teaches Logic
Stuck on a cell? Our hint system shows you the next logical move without just giving away the answer. Learn real solving techniques β not guesswork β and become a better player.
Pencil Marks & Auto-Note Mode
Jot down candidate numbers in each cell with pencil marks. Auto-note fills in all possibilities automatically so you can focus on scanning rows, columns, and 3x3 boxes for patterns.
Undo, Erase & Timer Tracking
Made a mistake? Undo moves instantly with no penalty. Track your solving time on the built-in clock. Erase individual cells or clear the whole board and start fresh whenever you want.
Dark & Light Themes for Eye Comfort
Switch between a sleek dark mode for late-night puzzling and a bright light mode for daytime sessions. Clean, grid-focused design keeps your eyes on the numbers without distractions.
Play Anywhere, No Download Required
Play sudoku online directly in your browser on desktop, tablet, or mobile phone. No app install, no sign-up, no subscription β just open the page and start solving puzzles instantly.
β Frequently Asked Questions
What is sudoku online?
sudoku online is a free browser-based number puzzle game where you fill a 9x9 grid with digits 1 through 9. Each row, column, and 3x3 subgrid must contain every digit exactly once. Our site offers unlimited puzzles across four difficulty levels with helpful tools like hints, pencil marks, and an undo button to support your solving journey.
How do you play sudoku online?
Select a difficulty level β easy, medium, hard, or expert β and a fresh puzzle loads on your screen. Click any empty cell and type a number from 1 to 9. Each number must appear exactly once in every row, every column, and every 3x3 box. Use pencil marks to note possible candidates. The goal is to fill the entire grid following these rules.
Is sudoku online completely free?
Yes! All puzzles on sudoku-online.cn are 100% free with no hidden costs. There is no subscription, no in-app purchases, and no account registration required. Just visit the site from any device and start playing unlimited sudoku puzzles immediately.
What are the difficulty levels available?
We offer four standard difficulty tiers: Easy, Medium, Hard, and Expert. Easy puzzles have the most pre-filled numbers and are great for beginners. Medium adds moderate challenge. Hard requires advanced techniques. Expert puzzles stretch even seasoned solvers to their limits with minimal starting clues.
Can using hints help me improve at sudoku?
Absolutely β our hint system is designed as a learning tool. Instead of simply revealing a number, it highlights which cell you should focus on next and explains the logical reasoning behind the move. Over time you will internalize techniques like scanning, cross-hatching, and candidate elimination without relying on guesswork.
How does pencil mark mode work?
Pencil marks let you note possible candidates in each empty cell. Turn on auto-note and the game fills in all valid candidates automatically based on existing numbers. You can then manually eliminate candidates as you deduce which numbers cannot fit β this is the same approach competitive solvers use to tackle the hardest puzzles.