Play Sudoku Online

Fill the grid so every row, column and 3 × 3 box contains the digits 1 to 9 once. Each puzzle here is generated on the spot and checked to have exactly one solution. Tap a square, then a number.

How to play sudoku

1. Tap a square and then a number, or use the keyboard (arrows to move, 1 to 9 to fill, Backspace to erase).
2. Matching rows, columns and boxes are highlighted to help you scan.
3. A wrong digit turns red. Press Hint to reveal one square.

How the puzzles are made

The page fills a complete random grid, then removes clues one at a time, keeping each removal only if the puzzle still has exactly one solution. Easy puzzles keep about 40 clues, medium about 32 and hard about 27. Fewer clues means longer chains of logic.

Beginner strategy

• Scan each box for a digit that has only one possible square (hidden single).
• Look for squares where only one digit fits (naked single).
• Work on the digit that already appears most often.

Play Sudoku Online quiz: 10 questions

Test yourself with 10 multiple-choice questions. Choose an answer and press Submit to see if you are right and why. Your score appears at the end.

Frequently asked questions

Are these sudoku puzzles free?

Yes, and unlimited: press New puzzle for another one.

Does every puzzle have one solution?

Yes. The generator checks uniqueness before showing the puzzle.

Can I play with a keyboard?

Yes. Arrow keys move, digits fill, Backspace erases.

Is there a solver?

Yes, the sudoku solver page solves any puzzle you type in and explains hints.

Does sudoku improve math skills?

It trains logical reasoning, patience and systematic checking, which help in problem solving.

Sources

• McGuire, Tugemann and Civario, There is no 16-clue Sudoku (2012), arXiv:1201.0749

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