Play sudoku online

Unlimited sudoku, four levels

This page gives you a fresh puzzle whenever you want one. Choose easy, medium, hard or expert above the grid, solve, and press New puzzle for the next. Unlike the daily sudoku, which is the same for everyone on a given date, these puzzles are picked at random from a large bank, so two people rarely get the same one unless they share a link.

The bank holds 4,000 unlimited-mode puzzles per level (16,000 in total), separate from the daily puzzles. Every one was generated by our own program, checked by a solution counter to make sure it has exactly one solution, and graded by a solver that works like a person: it tries the simplest techniques first and records the hardest one it needs. A puzzle only gets a level if that is exactly the hardest technique it requires, so “hard” means hard for a reason.

Puzzle codes and links

Each puzzle has a code, shown under the options. The address bar changes to something like play/#seed=48213&level=hard. Bookmark it to come back later, or send it to a friend to race on the same grid. Codes run from 0 to 999,999,999; codes above the size of the bank map to the same puzzles with the digits relabelled and the grid rotated or reflected, which changes how a puzzle looks but not how it is solved or how difficult it is.

Playing on a phone, tablet or computer

Tap or click a cell to select it, then use the number pad under the grid. On a keyboard, arrow keys move around the grid and the number keys fill cells. Notes mode (the pencil button, or the N key) switches the pad to small candidate numbers, which is how most people tackle harder puzzles. Undo and redo go back and forward through up to a thousand moves, so experimenting costs nothing.

The options under the grid let you decide how much help you get. Highlighting shows the row, column and box of the selected cell and every copy of the same digit, which makes it much faster to see where a number can still go. “Highlight mistakes” marks any number that doesn't match the solution as soon as you type it; leave it off if you prefer to find your own errors, and press Check when you want a one-time report.

Choosing a level

• Easy: singles only, with 36–40 givens. Ideal for learning or a five-minute break.
• Medium: adds pointing pairs, box/line reduction and pairs; 30–33 givens.
• Hard: can need triples, X-Wing or XY-Wing; typically around 25 givens.
• Expert: can need Swordfish, Jellyfish, XYZ-Wing, unique rectangles or simple coloring.

If a level feels like a wall, the hint button is designed to teach rather than just fill in a number: the first press names the technique and where to look, the second highlights the cells, and only the third makes the move. The strategy guides explain each technique with a worked example and practice puzzles.

Your progress stays with you, not with us

Unfinished games are saved in your browser as you play, up to 60 of them, and your solve times feed per-level stats. Nothing about your games is sent to a server, and you can delete all of it from the privacy page. If you would rather solve on paper, the printable sudoku page makes sheets of one, four or six puzzles with an answer key.