Sudoku Generator and Sudoku Maker

Generate a batch of puzzles with your settings, or type your own clues and check that the puzzle has one solution.

This free sudoku generator makes new sudoku puzzles in your web browser, in grid sizes from 4x4 to 16x16. It also works as a custom sudoku maker, where you type in your own clues and the tool checks them as you go. There is no sign-up and nothing to install. Puzzles are made on your device, and nothing is uploaded.

Use Generate puzzles when you want a set of ready-made puzzles at a chosen difficulty. Use Make your own when you want to create your own sudoku from scratch or from a puzzle you paste in. You can play what you make on the page or print it.

How to use the Sudoku generator

Choose a mode: Generate puzzles or Make your own.
In Generate puzzles, pick a grid size: 4x4, 6x6, 9x9, 12x12 or 16x16.
Pick a puzzle type: Classic, Diagonal (X) (6x6 and 9x9), Hyper (Windoku) (9x9) or Jigsaw (6x6 and 9x9).
Pick a difficulty: Easy, Medium or Hard. Expert is also available for classic 9x9.
Turn Symmetrical clue pattern on or off.
Set the number of puzzles, from 1 to 24.
Press Generate new puzzles. Each puzzle appears as a card with its clue count and difficulty.
On a card, use Play this puzzle to solve it on the page with Check, or Answer to see the solution. You can also use Copy as text (one row per line, a dot for a blank) or Download SVG.
To create your own, switch to Make your own. Type clues into an empty grid (classic, diagonal or hyper), or paste a puzzle. Repeated digits turn red, and the tool shows whether there are no solutions, exactly one, or two or more.
When there is exactly one solution, the tool shows the difficulty and the hardest technique needed. If there are still two or more, Suggest a clue adds a digit taken from one of the solutions.

Print all prints the puzzles and then the answer pages, with 1, 2, 4 or 6 puzzles per page on Letter or A4. In Make your own, Print gives the puzzle and answer. Copy link reproduces the same batch, so you can send it to someone else.

How to create a sudoku puzzle

A sudoku generator starts with a complete, valid grid that it builds at random. It then removes clues one at a time, keeping a removal only if the puzzle still has exactly one solution. Once no more clues can be removed, the generator rates it with a logic solver and tries again until the difficulty matches the setting you chose.

Every row, column and box must contain each digit once. Puzzle variants add their own rules, such as the diagonals in Diagonal (X), the extra windows in Hyper (Windoku), or the irregular regions in Jigsaw. The number of clues decides how hard a puzzle is to start, but it is not the whole story. On 9x9 grids, the generator’s measured clue counts are 37 to 40 for easy and 26 to 30 for medium and hard. On 4x4 grids, easy puzzles have 8 clues, medium 6, and hard 4 or 5. On 6x6 grids, the counts are about 18, 14 and 11. On 16x16 grids, they are about 141, 123 and 108 of the 256 cells. When Symmetrical clue pattern is on, clues are removed in matching pairs, which gives a balanced look.

On 9x9 grids, the site defines difficulty by the solving technique needed. Easy puzzles can be solved with naked and hidden singles alone. Medium puzzles need locked candidates (pointing or claiming) or naked and hidden pairs. Hard puzzles need triples, X-Wing, Y-Wing, Swordfish or XYZ-Wing. Expert puzzles have a unique solution but cannot be finished with those techniques, so they need guessing or more advanced methods.

How does a sudoku generator make sure there is only one solution?

It counts the solutions after each removal. If removing a clue leaves exactly one solution, the removal stays. If it allows two or more, the clue goes back in. This check is what keeps a generated puzzle fair, because a player never has to guess between two correct answers.

Make your own runs the same kind of check as you type. It reports no solutions, exactly one, or two or more. A puzzle with no solutions usually contains a clue that conflicts with another, which is why repeated digits are flagged in red. A puzzle with two or more solutions is missing clues, and this is the situation where Suggest a clue can help by adding a digit from one of the valid solutions.

Frequently asked questions

How do I make my own sudoku puzzle?

Open Make your own and type clues into the empty grid, or paste a puzzle you already have. Watch the solution count: you want exactly one. Once you reach that, the tool shows the difficulty and the hardest technique needed.

Can I print the puzzles I make?

Yes. Print in Make your own gives the puzzle and its answer. In Generate puzzles, Print all prints the puzzles first and then the answer pages, with 1, 2, 4 or 6 per page on Letter or A4.

Is this sudoku generator free to use?

Yes. It is free, requires no sign-up, and has nothing to install. It runs in your browser.

Does the tool upload my puzzles?

No. Nothing is uploaded, and puzzles are made on your device.

What is the difference between Generate puzzles and Make your own?

Generate puzzles creates batches of new puzzles for you, with settings for size, type, difficulty and count. Make your own lets you build or paste a puzzle yourself, with live checks on repeated digits, solution count and difficulty.

Can I make a 9x9 hyper sudoku or a 6x6 jigsaw?

You can generate both. Hyper (Windoku) is available on 9x9, and Jigsaw is available on 6x6 and 9x9. Jigsaw puzzles can be generated but cannot be drawn by hand in Make your own.

Printable sudoku - Use this when you want ready-to-print sudoku puzzles without setting any options.
Sudoku solver - Use this when you have a puzzle and want to see its solution.
Blank sudoku grid - Use this when you want an empty grid to fill in by hand.
Diagonal sudoku - Use this for puzzles where both main diagonals must also contain each digit once.
Hyper sudoku - Use this for 9x9 puzzles with four extra windows.
Jigsaw sudoku - Use this for puzzles with irregular regions instead of square boxes.
16x16 sudoku - Use this for a larger grid with 16 digits.
4x4 sudoku - Use this for a small grid that is quick to solve.