Sudoku — Play Free Online

About Sudoku

Sudoku is the number placement puzzle everyone knows: fill a nine-by-nine grid so that every row, every column and every three-by-three box contains the digits 1 to 9 exactly once. This version, Sudoku Plus, generates fresh puzzles at four difficulty levels and gives you the tools serious players expect, including pencil marks for candidates, an error highlighter and a hint button for when you are truly stuck.

Puzzles always have a single solution and never require guessing, so a stuck moment means there is a logical step you have not spotted yet. Timers and statistics are there if you want them and easy to ignore if you do not.

How to Play Sudoku

1. Pick a difficulty and a fresh grid loads.
2. Select a cell and enter a digit, or switch to pencil mode to note candidates.
3. Work through rows, columns and boxes using elimination.
4. Fill every cell correctly to finish the puzzle.

Controls

• Mouse or touch: select a cell.
• Number keys or on-screen pad: enter a digit.
• Pencil toggle: switch between final numbers and candidate notes.
• Undo and erase buttons are available.

Tips and Tricks

• Start with rows, columns or boxes that already have the most digits filled in.
• Look for a digit that can go in only one cell of a box; those are the easy wins.
• Pencil marks are worth the time on medium puzzles and above.
• When stuck, check every cell that has only two candidates. One of them usually breaks the deadlock.

Sudoku FAQ

Are the puzzles random?

Yes. A new grid is generated each time, so you never run out.

Does it tell me when I make a mistake?

Mistake checking can be turned on or off. With it on, wrong digits are highlighted immediately.

Can I save a puzzle and come back?

Your current grid is kept in the browser, so reloading the page picks up where you left off.