How to Play Sudoku Online



Play Sudoku Online

--> Play Sudoku Online at Sudoku is a simple game to learn and a difficult game to master.

The objective of Sudoku is to enter a number from 1 through 9 in each square such that every row, column, and 3×3 block contains exactly one of each number.

Word Sudoku adds a twist which makes the game a little more interesting. To play Word Sudoku, use letters instead of numbers. Some of the squares in the puzzle are shaded and those squares contain letters that can be unscrambled to find a hidden clue. If you can figure out the clue before all of the shaded spaces have been filled in, the remaining letters can be used as clues to finish the Sudoku grid.

The hidden clue may use some of the letters more than once and some may not be used at all.

Starting A New Puzzle

Choose either Word or Number as the Puzzle Type, then click the button that corresponds to one of three levels of difficulty: Easy, Hard, or Harder. All the Sudoku puzzles at have one unique solution.

New puzzles will already have some values in some of the squares. These are clues and are arranged in a way that guarantees the puzzle can have only one solution. The objective is to type one value in each open square while abiding by the Sudoku rules that each row, column, and 3×3 block contain exactly one of each value.

Finding a Puzzle

It is possible to find a specific puzzle by number. This is useful if you’ve printed a puzzle and want to return to the puzzle at Just type the puzzle # in the field labeled ‘Puzzle #’ and click Find.

If you do not remember the puzzle #, just click Resume Last Puzzle and the last puzzle visited will be reloaded along with pencil marks and guesses. This feature only works when using the same browser and computer that was used when the puzzle was last visited.

Pencil Marks

Solving Sudoku puzzles requires tracking all of the values that can or cannot be played in each square. If you can do that in your head you should audition for The Big Bang Theory.

The rest of us will need to keep track of our work, and that can be done simply by typing more than one value in an open square. Squares with more than one value will be ignored when checking the validity of the puzzle.

Enter the same letter twice in the same box to distinguish a pencil mark from a clue.