Free Sudoku Online Without Sign-Up

Can you play immediately?

Yes. Open Classic Sudoku, choose Easy, Medium, Hard or Expert and start solving without creating an account. The game supports mouse, touch and keyboard input, so the same puzzle works on a phone, tablet or computer.

What is included?

• A standard 9×9 Sudoku grid with four difficulty levels.
• Notes for candidate numbers, undo, erase and optional hints.
• Visual themes and a readable number pad.
• A separate printable generator and a playable Kalkudoku variant.

How should beginners start?

Choose Easy and first scan rows, columns and 3×3 boxes that already contain many numbers. Place a digit only when its position is certain. Notes are useful when a cell has two or three possible values, but avoid filling every cell with candidates before checking for obvious singles.

Why play in the browser?

Browser Sudoku removes the installation and account steps. You can start a short puzzle, print a set for later, or switch to Kalkudoku without downloading separate apps. Progress is designed for the current device, so clearing browser data may remove locally stored preferences or statistics.

For a structured introduction, read the Sudoku rules, the beginner guide and the explanation of difficulty levels.