Sudoku

Free sudoku with a daily puzzle

Sudoku has four levels and a new daily puzzle. Fill the grid so every row, column and 3×3 box holds the numbers 1 to 9 once each. Each puzzle is made fresh in your browser and has exactly one answer that you can reach by logic alone, so you never need to guess. Levels are graded by the techniques a puzzle needs, not just by how many numbers it starts with, so Hard really is harder than Medium.

What's in the game

• Four levels: Easy needs only singles. Medium adds pairs and pointing. Hard needs techniques like triples, X-Wing or XY-Wing. Master needs several of those, or a Swordfish.
• A daily sudoku that's the same for everyone on the same day, with a streak to keep and a result you can share.
• Notes that clear themselves as you fill in numbers, plus undo and highlighting.
• Hints that teach: each hint explains the technique behind the next step, not just the answer.
• A choice of mistake checking, and a dark or light theme.

Tips

• Look for singles first: a square that can only hold one number, or a number with only one place left in a row, column or box.
• Add notes once the easy numbers run out. They make pairs and other patterns much easier to spot.
• Two squares in a row that can only hold the same two numbers form a pair. Those two numbers can't go anywhere else in that row.
• The daily allows three mistakes and no hints, so check your notes before you commit a number.