Play Sudoku Classic Online Free

About Sudoku Classic

Sudoku Classic brings the world-famous number puzzle to your browser with a clean, distraction-free interface perfect for focusing on logical deduction. Every puzzle is carefully generated to have exactly one solution, ranging from gentle warm-ups to fiendishly difficult challenges that require advanced solving techniques. The game includes helpful features like pencil marks for noting possible numbers, error highlighting, and a hint system that guides you without giving away the answer. Track your solve times across different difficulty levels and compete against your personal bests. Daily puzzles give you a fresh challenge every day, while the unlimited puzzle generator ensures you never run out of grids to solve.

How to Play Sudoku Classic

Fill the 9x9 grid so every row, column, and 3x3 box contains the numbers 1-9. Click a cell to select it, then type a number. Use pencil mode to note possible numbers.

Tips & Tricks

Start with rows, columns, or boxes that already have the most numbers filled in. Use pencil marks to track possibilities. Look for naked singles — cells with only one possible number.

Frequently Asked Questions