Sudoku

How to play sudoku

Every row, every column and every box holds each number once: 1 to 9 on a 9×9 grid, 1 to 6 on a 6×6 mini sudoku. The boxes are the areas inside the thick lines. Some numbers are given at the start, and you find the rest.

The puzzle is solved when every cell is filled and no number repeats in a row, column or box.

Notes are small pencil marks for the numbers a cell could still be. When you place a number, Owlpuzzles takes it out of the notes in the same row, column and box.

Tips for faster solves

Look for the last number in a row

When a row, column or box has one empty cell left, only one number can go there. Easy days have plenty of these.

Find the only place for a number

Pick a number and a box. Cross off every cell in the box that sees that number in its row or column. If one cell is left, the number goes there.

Use notes on harder days

Midweek and weekend grids need more than these. Pencil in what each cell could be, then look for two cells in a row with the same two numbers. Those two numbers can’t go anywhere else in that row.

A new sudoku every day

Owlpuzzles has a new sudoku every day at midnight in your time zone, and it gets harder through the week. Monday and Tuesday are 6×6 mini sudokus. Wednesday and Thursday are 9×9 grids that need notes. Friday to Sunday are hard 9×9 grids with techniques like X-wings.

Every grid is solved by a computer the way a person would before it goes out, so it has one answer and never needs a guess. When one a day isn’t enough, there are 300+ sudoku levels from easy to hard, and unlimited sudoku for as many as you like.

Mini sudoku

A mini sudoku is a 6×6 grid with boxes two rows tall and three columns wide, using the numbers 1 to 6. It’s the same game, done in a few minutes. LinkedIn’s daily Mini Sudoku is this size. On Owlpuzzles the Monday and Tuesday sudokus are mini sudokus, and so are the easy levels.

Questions about sudoku

Is this sudoku free?

Yes. It plays in your browser on a phone or a computer, with nothing to install and no sign-up. A free account only keeps your streak and stats on every device.

How many numbers does a sudoku start with?

It depends on the day. Easy grids give more numbers to start from. Hard 9×9 grids give fewer, but always enough for exactly one answer.

Can I play a mini sudoku?

Yes. The Monday and Tuesday dailies are 6×6 mini sudokus, and so are the easy sudoku levels.

Can I print sudoku puzzles?

Yes. The printable sheets have sudoku from easy to hard, with the answers on the second page.

What if I make a mistake?

Repeated numbers show in red as you play. You can turn that off in the settings if you’d rather find them yourself.

More puzzles to try

Killer sudoku swaps the given numbers for cages with sums. Calcudoku has cages that add, subtract, multiply or divide, and kakuro is a crossword made of sums.