Sudoku4 per page
Printable sudoku
A page of four classic 9 × 9 sudoku with the difficulty and the number of puzzles per page under your control. It suits adults and older children who want a fresh batch of number puzzles to print.
- Fresh problems every time
- Answer key on its own page
- Print or PDF, Letter or A4
- Free, no sign-up
On this page
Sudoku needs nothing but a pencil and a little patience. This page builds a new set each time you press the "New puzzle" button, so you can print as many different sheets as you need without hunting for a source.
What prints
The sheet is titled "Medium Sudoku" when it opens, and the title changes to match the difficulty you pick. Under it comes one instruction: the blanks take the numbers 1 to 9 so that no row, column or 3 × 3 box repeats one. Four grids sit in two columns, each labeled Puzzle 1 to Puzzle 4. Heavy lines mark the nine boxes and thin grey lines mark the single cells. The starting numbers are printed in bold.
The answer key is its own page, with each square filled and your missing numbers shown in color against the bold clues.
The settings
- Grid: the small 4 × 4 and 6 × 6 boards are there too, but this page starts on the full 9 × 9.
- Difficulty: Medium is selected, with Easy and Hard as the other two.
- Puzzles per page: a choice of 1 (large print), 2, 4 or 6, starting at 4.
How the puzzles are made
The generator first fills a complete valid grid at random. It then takes numbers away one at a time in random order and, after each removal, runs a solver. A number only stays removed if the puzzle still has exactly one solution. The target is about 38 clues for Easy, 31 for Medium and 26 for Hard on a 9 × 9 grid. Because removal stops early whenever the next one would break uniqueness, a given puzzle can end up with a few more clues than the target.
That check matters at the table. You never reach a point where two answers both fit, so every puzzle can be finished by logic alone, with no guessing.
Tips for solving
Scan for a number that already appears in several rows and columns, then see where it can still go in the remaining boxes. Pencil small candidate numbers in the corner of a square only when you get stuck, and rub them out as the grid fills. Work in pencil on a clipboard or a hard surface so the lines do not dent the page.
Worked example: a lunch-break set
Marcus keeps a folder at work and wants a puzzle that takes about twenty minutes. He leaves the page on Medium, 9 × 9, and sets Puzzles per page to 2 so each grid is bigger. He presses "New puzzle" until the first grid has a row with only two blanks, prints two copies for a coworker, and uses the second as a race. Afterward they check against the key page and circle any square where they differed.
Related pages
If this level is too hard or too easy, try easy sudoku or hard sudoku. For a different kind of puzzle, the word search maker builds a grid from your own words.
Sources
- NRICH, University of Cambridge: Sudoku-style puzzles nrich.maths.org