Printable sudoku
30 classic 9 by 9 sudoku, an even split across the three levels, printed one to a page so the grid is big enough to write in comfortably.
30 printable sheets ·
Checked and published by 
Nora Quill
What is on this page
Classic 9 by 9 sudoku, one to a page, printed large enough to write in comfortably with an ordinary pen. The set is split evenly across three levels, and every puzzle ends with its own answer page inside the same download.
The three levels are a real difference
Difficulty in sudoku comes down to how many numbers you start with. These are the actual figures:
- Easy, around 42 clues. Roughly half the grid is filled before you begin. You can usually work the whole thing by scanning rows and columns for the only square a digit can go in.
- Medium, around 33 clues. Scanning alone runs out partway. You start needing to note which digits a square can still take.
- Hard, around 26 clues. Two thirds of the grid is empty. Pencil marks stop being optional.
Each card gives the exact clue count for that board, plus two measurements you will not usually find: how many empty squares already accept only one digit, which tells you how fast the opening will go, and how few clues the barest row was left with, which tells you where not to start.
Every puzzle has exactly one solution
This is the part worth caring about, and the part that is easy to get wrong. Each grid is built by starting from a complete, valid solution and removing numbers one at a time in random order. A number is only left out if the puzzle still has exactly one solution without it. If removing it would allow two different valid answers, it goes back.
The result is that no puzzle here ever requires a guess, and the answer sheet is genuinely the answer rather than one of several possibilities. A sudoku with two solutions is not a hard sudoku, it is a broken one, and plenty of free collections ship them because the check is easy to skip.
Solving without guessing
Three techniques cover almost everything on this page:
- Single position. Take a digit, look at a box, and rule out every row and column that already contains it. Often only one square survives.
- Single candidate. Take an empty square and list what could go there. If only one digit can, it goes.
- Pairs. If two squares in a unit can only take the same two digits, no other square in that unit can take either of them.
Easy puzzles fall to the first alone. Medium needs the second. Hard usually needs the third somewhere.
Printing
Set scaling to 100 percent rather than "fit to page", so the grid stays as large as it was drawn and the squares keep enough room to pencil in candidates. The pages carry a 15mm margin, so they print on A4 and on US Letter without cropping. Black and white at normal quality is fine; nothing on the page depends on colour.
If you like working with pencil marks, print at the largest size your printer allows and do not use draft mode, which can thin the grid lines.
Coming back to a puzzle
Each description ends with a puzzle number identifying that exact board. Note it if you want the same grid again, or want to give somebody else the same one.
How to use these sheets
- Pick a sheet and press Print. The file is a PDF sized for A4 and Letter paper.
- Print it in black and white at normal quality. None of these sheets need colour ink except the colour by number pages.
- Keep the answer page for yourself, or print it too if you want to check the work later.
Common questions
Does every sudoku here really have just one solution?
Yes. A cell is only left blank if the puzzle still solves uniquely without it, and that count is verified again before the sheet is published. The answer page you download is the answer, not one of several possibilities.
What actually changes between easy and hard sudoku?
The number of givens, the digits already filled in when you start. Easy sudoku open with plenty of them and some squares you can fill straight away; hard sudoku leave far fewer and make you work for every digit. The tier changes the board itself, not just the label on the page.
Can I print these for a class or a sudoku club?
Yes, as many copies as you need, handed out for free. Classroom use is expressly covered, along with home use. The only lines are the usual ones: no selling the sheets and no re-uploading the PDFs elsewhere, as the licensing page spells out.
I have printed them all. When do more arrive?
Sudoku batches go up once every board has passed the single-solution check, and the new and popular printables page is where they appear first. If you run dry in between, the Maze Maker generates unlimited fresh printable mazes with solutions while the next sudoku batch is being checked.
How do I print a sudoku grid so it stays sharp?
Black and white at normal quality is enough: the grid lines are drawn heavy on purpose so they survive even draft mode, and no colour ink is involved. If the grid prints faint or the page comes out shrunk, the how to print guide covers scaling and margins.
Is there a smaller sudoku for a young child?
Yes. The 4x4 sudoku page uses sixteen squares and the numbers 1 to 4, with squares up to forty millimetres across, and a third of those sheets replace the digits with shapes, arrows or pictures so a child who cannot read numbers yet can still solve one. Every one of them has a single solution too.