Printable 4×4 Sudoku Puzzles

What is in the printable 4×4 Sudoku PDFs?

Three files, one per level: Easy, Medium and Hard. Each is 63 US Letter pages in black and white: a cover with the rules, 100 puzzles two to a page on pages 2–51, and the solutions nine to a page on pages 52–63. No sign-up, no password. Each grid is printed 4.35 inches (11 cm) wide, so a cell is a little over an inch across, room for a young child’s handwriting.

The rule, as the cover puts it: every row, column and 2×2 box holds the digits 1 to 4 once each. The puzzle itself, from how many 4×4 Sudokus exist to the fewest clues one can have, is covered on the 4×4 Sudoku game page.

We did not collect these puzzles; we generated them. Each was dealt by the same generator as our online 4×4 game, then counted by a separate solver that shares no code with it, and only a puzzle with exactly one answer went into a file.

Which 4×4 PDF should you print: Easy, Medium or Hard?

Start a first-timer on Easy, whatever their age. The levels differ in how many numbers are printed, and so in how much you can see at once, not in technique: all 300 puzzles can be finished with one check, the naked single, and so can every 4×4 Sudoku there is. For the game page we checked all 13,579,680 of them.

The 100 puzzles of each PDF, as printed: medians, range in brackets. A cell can be filled at once when its row, column and box already show three different digits; a pass fills every such cell, then looks again. Each file: a cover, 50 pages of puzzles, 12 of answers.

So moving up a level asks for patience, not a new skill. An Easy puzzle usually lets you fill five of its six empty cells straight away, and 23 of the 100 can be finished in one pass. A typical Hard puzzle shows three cells to start from, and 5 of the 100 show just one. Print Hard for someone who already finishes Easy without help and wants the hunt to take longer.

Hard Puzzle 1 is the only Hard puzzle with six numbers given. The generator aims for five, but never removes a number if that would let in a second answer, and on that board all six are needed. 32 of the 100 Hard puzzles are like that, with no spare number at all.

Where do you start on a 4×4 Sudoku worksheet?

Pick an empty cell and read its row, its column and its 2×2 box. If between them they already show three different digits, the missing one is the answer: write it in. If not, move on to another cell. Every digit you write gives its neighbours something new to see, so go round again until the grid is full. Here is Hard Puzzle 1 done exactly that way.

On this board the digit that is not printed at all went in first: all four 4s, before anything else. If a child gets stuck, ask them to name the digits a cell can see. Fewer than three different ones means that cell is not ready yet, and as long as everything written so far is right, another cell always is. Asking where a digit can go in a row or box instead, a hidden single, is just as correct, but a 4×4 never needs it.

How do you check a 4×4 Sudoku against the answer key?

Check the grid itself before turning to the back. A 4×4 has twelve groups to look at: four rows, four columns and four boxes, each needing 1, 2, 3 and 4 once. If all twelve pass and none of the printed numbers has been changed, the grid is right, because each of these puzzles has only one answer. That makes the self-check a real test, worth learning before the answers are in reach.

Then find the solution. They run in order, nine to a page and labelled by number: Puzzles 1–9 on page 52, 10–18 on page 53, and so on to Puzzle 100 on page 63. If a digit differs, find the row, column or box where it now clashes, rub out back to the last digit the solver can explain, and go on from there.

Printing tips: A4 paper, page ranges and reuse

• A4 or Letter. The files are US Letter. The margins are wide enough that A4 loses nothing at actual size; “fit to page” works too, about 3% smaller.
• Puzzles without answers. Print pages 2–51 and keep 52–63 back. Puzzle n is on page 1 + n/2, rounded up, so Puzzles 1–10 are pages 2–6.
• No colour ink. Everything is black, white and grey, so a mono printer or a photocopier does the job.
• Use a sheet again. Slide a page into a clear sheet protector, or laminate it, and solve with a dry-erase marker.
• A different layout. For A4 from the start, more puzzles to a page or a large-print sheet, the Sudoku generator makes 4×4 sheets to order, with answer keys.

Using 4×4 Sudoku sheets in class and at home

Give everyone the same puzzle number and the checking can happen out loud: one pupil reads the row, another the column, a third the box, and the group agrees on the digit before anyone writes it. Mixed groups can work from different files on the same day; the method is the same at every level, and only the starting count changes.

Keep sessions short: one puzzle finished and explained beats a page rushed. When a child can say why each digit goes where it goes, move up a level, and when Hard feels easy, move up a size. Printable 6×6 Sudoku uses the same rule with six digits and 2×3 boxes, and the full printable Sudoku collection goes on to 9×9 and beyond.

Our Sudoku for Kids page covers teaching the rule step by step. For instant feedback instead of an answer key, the online 4×4 game marks a wrong digit red the moment it goes in.