Sudoku

Free online sudoku with no sign-up: four difficulty levels and a daily sudoku.

Sudoku is played on a 9 × 9 grid divided into nine 3 × 3 boxes. Some numbers are given at the start.

Fill the empty cells with the numbers 1 to 9 so that every row, every column and every box contains each number exactly once. Every sudoku on this page has exactly one solution, and you can reach it by logic without guessing.

• Select a cell, then a number below or next to the grid. On a computer you can also type the number and move with the arrow keys.
• Notes (or the N key) let you write small candidate numbers in a cell. When you place a number, it is removed from the notes in the same row, column and box.
• If the same number appears twice in a row, column or box, the cells turn red. In the settings you can also choose to mark wrong numbers right away.
• Undo takes moves back all the way to the start, and Erase clears the selected cell.
• An unfinished sudoku is saved in your browser, so you can continue later on the same device.

The level depends on the hardest technique the puzzle needs.

• Easy: 36 to 41 numbers are given. Look for a cell where only one number fits, or a number that has only one place in a box, row or column.
• Medium: you need notes and techniques such as pointing pairs and naked pairs.
• Hard: you need patterns such as X-Wing, Skyscraper or XY-Wing.
• Expert: you need techniques such as XY-Chain, W-Wing or Swordfish. These puzzles still solve by logic.

The daily sudoku is the same for every player, and a new one starts at midnight. Each level has its own daily puzzle, and your statistics show how many days in a row you have solved it.

1. Start with the boxes: check where a missing number can still go.
2. Do the same for rows and columns.
3. When the easy places run out, write the possible numbers of each cell in notes.
4. Look for pairs: if only the same two numbers fit in two cells of a row, column or box, those numbers cannot go in any other cell there.
5. If you get stuck, press Hint. It shows the next logical step and names the technique, so next time you can spot the pattern yourself.

Is this sudoku free?
Yes. Play as many puzzles as you like with no sign-up and nothing to download. It works on phones, tablets and computers.

What is the daily sudoku?
The daily sudoku is the same for every player, and a new one starts at midnight. You can solve it on all four levels.

What is the difference between easy, medium, hard and expert sudoku?
The level depends on the hardest technique the puzzle needs. Easy puzzles only need cells or numbers with a single option. Medium needs notes and pairs, hard needs patterns like X-Wing, and expert needs chains.

How do you solve a sudoku?
First look for cells where only one number fits and numbers that have only one place in a box. When there are none left, fill in notes and look for pairs. If you get stuck, a hint shows the next step.

How do notes work?
Press Notes or the N key and choose the numbers that could fit in the cell. They appear small in the cell. In the settings you can also fill in all possible numbers at once.

How does the hint work?
The hint first tells you if a number is wrong. Otherwise it shows the next logical step and the name of the technique, such as hidden single, pointing pair or X-Wing. Press Show number to place the number.

Is an unfinished sudoku saved?
Yes. The game is saved in your browser, and you can continue on the same device where you left off. Your statistics are saved in the browser too.

Does every sudoku have only one solution?
Yes. Every puzzle has been checked: it has exactly one solution, and you can solve it by logic without guessing.

We also make apps for phones, TVs and computers.