Game
MathSudoku
Play Sudoku online for free. Multiple difficulty levels, hints, notes mode, and statistics tracking. Challenge your brain with the classic number puzzle game.
Difficulty
Medium
Time
0:00
Mistakes
0/3
Progress
0/81
Click 'New Game' to start playing!
How to PlaySelect a Cell
Click or tap any empty cell to select it. Use arrow keys to navigate.
Click or tap any empty cell to select it. Use arrow keys to navigate.
Fill Numbers
Click numbers 1-9 on the numpad or use keyboard to fill cells.
Click numbers 1-9 on the numpad or use keyboard to fill cells.
Notes Mode
Toggle notes mode to add pencil marks for possible numbers.
Toggle notes mode to add pencil marks for possible numbers.
Sudoku Rules
Fill every row, column, and 3x3 box with numbers 1-9 without repeating.
Fill every row, column, and 3x3 box with numbers 1-9 without repeating.
Statistics0
Games Played
0
Games Won
--:--
Best Time
0%
Win Rate
Have feedback? Report bugs, suggest features, or share your thoughts — we read them allWhat is Sudoku?
Sudoku is a logic-based number placement puzzle that has captivated millions worldwide. The game consists of a 9x9 grid divided into nine 3x3 boxes. The objective is to fill every row, column, and 3x3 box with the numbers 1 through 9, with each number appearing exactly once in each row, column, and box. Our online Sudoku game offers multiple difficulty levels, helpful features like hints and notes mode, mistake tracking, and detailed statistics to help you improve your solving skills. Try also our Dice Roller and Snake Game.
Key Features
- Four difficulty levels: Easy, Medium, Hard, and Expert
- Notes mode for pencil marks and candidate tracking
- Hint system with 3 hints per game
- Mistake counter with 3 lives per game
- Undo functionality to reverse moves
- Auto-highlight of related cells (same row, column, and box)
- Same number highlighting for easy tracking
- Progress tracking showing filled cells
- Game timer to track your solving speed
- Comprehensive statistics with win rate and best time
- Keyboard support for faster gameplay
- Mobile-friendly touch controls
- Dark mode support
- No registration required - play instantly
How to Play Sudoku
- Click 'New Game' to start with a fresh puzzle at your chosen difficulty
- Click or tap on any empty cell to select it
- Use the number pad below the grid or press keys 1-9 to enter a number
- The game will highlight incorrect entries in red
- Use Notes mode (pencil icon) to mark possible candidates in cells
- Press the hint button if you're stuck (3 hints available per game)
- You can make up to 3 mistakes before the game ends
- Use the Undo button to reverse your last move
- Complete the puzzle by filling all 81 cells correctly
- Try to solve faster and with fewer hints to improve your statistics
Sudoku Tips & Strategies
- Start with Easy puzzles to learn the basic techniques
- Look for 'naked singles' - cells where only one number is possible
- Scan rows, columns, and boxes for 'hidden singles'
- Use notes to track candidates when puzzles get harder
- Focus on boxes, rows, or columns that are almost complete
- Look for numbers that appear 8 times to find the 9th placement
- Practice the 'pointing pairs' technique for intermediate puzzles
- Learn X-wing and Swordfish patterns for expert puzzles
- Don't guess - Sudoku puzzles have logical solutions
- Take breaks if you're stuck - fresh eyes often spot solutions
Frequently Asked Questions
Sudoku is played on a 9x9 grid divided into nine 3x3 boxes. The rules are simple:
1. Fill every empty cell with a number from 1 to 9
2. Each row must contain all numbers 1-9 without repetition
3. Each column must contain all numbers 1-9 without repetition
4. Each 3x3 box must contain all numbers 1-9 without repetition
Every valid Sudoku puzzle has exactly one solution that can be found through logic alone - no guessing required.
1. Fill every empty cell with a number from 1 to 9
2. Each row must contain all numbers 1-9 without repetition
3. Each column must contain all numbers 1-9 without repetition
4. Each 3x3 box must contain all numbers 1-9 without repetition
Every valid Sudoku puzzle has exactly one solution that can be found through logic alone - no guessing required.
Our Sudoku game offers four difficulty levels:
• **Easy**: ~35 cells removed, perfect for beginners
• **Medium**: ~45 cells removed, requires basic techniques
• **Hard**: ~52 cells removed, needs intermediate strategies
• **Expert**: ~58 cells removed, demands advanced techniques
Higher difficulties have fewer starting numbers, requiring more complex solving strategies.
• **Easy**: ~35 cells removed, perfect for beginners
• **Medium**: ~45 cells removed, requires basic techniques
• **Hard**: ~52 cells removed, needs intermediate strategies
• **Expert**: ~58 cells removed, demands advanced techniques
Higher difficulties have fewer starting numbers, requiring more complex solving strategies.
Notes mode (pencil marks) helps you track possible candidates for each cell:
1. Click the pencil icon to enable notes mode
2. Select a cell and enter numbers 1-9 to add them as notes
3. Click a noted number again to remove it
4. Enter a final answer to clear notes in that cell
5. When you enter a correct number, related notes are automatically removed
Notes are essential for solving harder puzzles where you need to track multiple possibilities.
1. Click the pencil icon to enable notes mode
2. Select a cell and enter numbers 1-9 to add them as notes
3. Click a noted number again to remove it
4. Enter a final answer to clear notes in that cell
5. When you enter a correct number, related notes are automatically removed
Notes are essential for solving harder puzzles where you need to track multiple possibilities.
Our game tracks mistakes to add challenge:
• You have 3 lives (mistakes allowed) per game
• Wrong numbers are highlighted in red
• The mistake counter updates immediately
• Game ends if you make 3 mistakes
• Mistakes are counted in your final statistics
This encourages careful thinking rather than trial-and-error approaches.
• You have 3 lives (mistakes allowed) per game
• Wrong numbers are highlighted in red
• The mistake counter updates immediately
• Game ends if you make 3 mistakes
• Mistakes are counted in your final statistics
This encourages careful thinking rather than trial-and-error approaches.
Hints help when you're stuck:
• You get 3 hints per game
• Click the hint button to reveal one correct number
• The hint fills a random empty cell with the correct answer
• Hints used are tracked in your game statistics
Try to solve puzzles with fewer hints to improve your skills!
• You get 3 hints per game
• Click the hint button to reveal one correct number
• The hint fills a random empty cell with the correct answer
• Hints used are tracked in your game statistics
Try to solve puzzles with fewer hints to improve your skills!
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