How to Play Sudoku - Rules & Tips

Learn the rules and master the controls in a few minutes.

100% free · No account or registration · Safe and fun for kids and families

The objective

Fill the 9×9 grid so that every row, every column, and every 3×3 box contains the digits 1 through 9, with no repeats.

Each row, column, and 3×3 box must contain 1–9 once.

Rules

  • Each row must contain 1–9, without repetition.
  • Each column must contain 1–9, without repetition.
  • Each of the nine 3×3 boxes must contain 1–9, without repetition.
  • Pre-filled cells (given at the start) cannot be changed.

Difficulty levels

Choose how many cells are already filled. Fewer givens means a harder puzzle.

Easy More givens
Medium Balanced
Hard Fewer givens
Expert Toughest

Controls & actions

Select a cell

Click an empty cell to select it. Use the number pad or keyboard after selecting.

Number pad / Keyboard

Press 1–9 to enter a number. Backspace or Delete to clear.

Notes

Turn on Notes mode, then tap a number to add or remove a candidate in the cell.

Erase

Clear the selected cell. Given numbers cannot be changed.

Undo

Revert your last move. Multiple undos are supported.

Hint

Reveal the correct number for the selected empty cell.

Stats

Timer

Shows how long you've been playing the current puzzle.

Mistakes

Wrong entries are counted. After 3 mistakes the game ends — start a new game to try again.

Frequently asked questions

The game ends. You can start a new game (same or different difficulty) from the New Game menu and try again.

Yes. Notes help you track candidates in cells. The Hint button reveals the correct number for the selected empty cell. You can use both in the same puzzle.

No. Pro Sudoku is free and requires no login or registration. Just pick a difficulty and start playing.

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