Sudoku Online
Free online Sudoku puzzles. Choose between Hard and Extreme levels and beat the clock.
Play Free Sudoku Online
Welcome to our free online Sudoku game. Challenge your brain with extreme 9x9 Sudoku puzzles available in two brutal difficulty levels: Hard and Extreme. Use the on-screen number pad or your keyboard to fill the grid, get hints when you're stuck, and race the built-in timer to solve each puzzle. Works on desktop, tablet, and mobile browsers.
How to Play Sudoku
The goal of Sudoku is to fill every empty cell in the 9x9 grid with digits from 1 to 9. Each row, each column, and each of the nine 3x3 boxes must contain each digit exactly once. Start with a Hard puzzle if you're experienced, or Extreme if you're a master.
Number Pad
Tip: on desktop, type 1–9 or press Backspace to erase.
How to Play Sudoku
Sudoku is a logic-based number puzzle. The objective is simple: fill every empty cell of the 9x9 grid with the digits 1 through 9, while making sure that each number appears exactly once in every row, every column, and every 3x3 box.
Difficulty Levels
- Hard – A brutal challenge for experienced players with very few clues.
- Extreme – The ultimate test; generates puzzles with a highly restricted number of clues.
Tips for Masters
- Scan rows, columns, and boxes to find where a digit is missing.
- Start with the cells that have the most given digits around them.
- Use the Hint button if you get stuck on a single cell.
- Watch for the red highlight — it warns you when a number breaks a rule.
Frequently Asked Questions
What difficulty levels are available?
You can choose between two extreme levels: Hard and Extreme.
Is this Sudoku game free?
Yes — completely free. No account, sign-up, or download required.
Does it work on mobile?
Yes. The interface is fully responsive and includes a touch-friendly number pad.
Can I use my keyboard?
Absolutely. Press 1–9 to place a digit, Backspace to erase, and the arrow keys to move around the board.
How are puzzles generated?
Each puzzle is generated uniquely using a well-known Sudoku generation library, then solved to provide a canonical solution for hints and validation.