Printable 12×12 Sudoku Puzzles

What is in each printable 12×12 Sudoku PDF?

Each of the four files holds 100 puzzles on 76 US Letter pages: a cover with the rules on page 1, the puzzles two to a page on pages 2 to 51, and the solutions four to a page on pages 52 to 76. Every puzzle is numbered, and its solution carries the same number. The pages are black and white, and each file is under half a megabyte.

The grid is the usual 12×12: every row, every column and every box of 3 rows by 4 columns holds the numbers 1 to 12 once each. On the puzzle pages a grid is 11 cm (4.35 in) wide, so each square is about 9 mm across; on the solution pages the squares are 7.5 mm.

How were these 12×12 puzzles made and checked?

We dealt them ourselves, with the generator behind our online 12×12 Sudoku, run from a fixed seed so the same command rebuilds the same files. Before a puzzle went into a PDF it had to be proven to have exactly one answer, by code that shares nothing with the generator. A puzzle that failed would have been dealt again; none did.

The solution pages print the stored answers those checks confirmed. The PDFs at these links until October 2026 were made another way: an older script removed numbers down to a fixed count and never checked that a puzzle still had only one answer. Printouts from before then are different puzzles from the ones described here.

How hard is each level on paper?

The four levels are dug by different rules, so the number of givens tells you less than you would expect. We ran all 100 puzzles of each PDF through a solver that knows naked singles, hidden singles, locked candidates, naked pairs and triples, and the X-Wing, and counted where each puzzle stopped.

All 100 puzzles of each PDF. Singles are naked and hidden singles; a further step is locked candidates, naked pairs or triples, or an X-Wing. Puzzles beyond our solver still have exactly one answer.

Hard prints more numbers than Medium and is still harder. Medium puzzles are dug out one number at a time for as long as singles can still finish them, which takes them down to 44–51 givens. Hard puzzles keep 57, but those 57 are not chosen with singles in mind, and half of them stall when the singles run out. Expert digs to about the same count as Medium with no such rule, and just one of its puzzles falls to singles.

What do the hardest Hard and Expert puzzles need?

More than the solver above knows: 31 Hard puzzles and 88 Expert ones go beyond it, and where it stalls on an Expert puzzle, a median of 75 of the 144 squares are still empty. We then tried a wider set of named techniques on those 119, from hidden pairs to Swordfish and simple colouring. They finished only 5 more Hard puzzles and 3 more Expert.

The rest gave way to a test. Pick a square with two or three candidates, pencil one of them in lightly, and follow the singles and locked candidates it forces. If a row, column or box ends up with no place left for some number, the candidate was wrong and can be crossed out. Our solver finished every remaining puzzle in both PDFs by adding that test to the techniques above, one candidate at a time, never two at once.

On paper that is slow work, so test in a corner of the square and erase the whole trail when it breaks. If you know singles and want a step up without a wall, Hard is the next PDF after Medium: half its puzzles need nothing more. Expert assumes you are happy testing candidates.

Where do you start on a printed 12×12?

With the fullest row, column or box. The fewer numbers it is missing, the shorter the list you have to test, and on paper a short list is everything: write the missing numbers in the margin beside the row, then check each one against the columns and boxes of the row’s empty squares. Here is that method on the first puzzle in the Easy PDF:

The 9 is a hidden single in its row and the 7 is a naked single, the only two kinds of move an Easy or Medium puzzle needs from start to finish. Puzzle 1 offers eleven squares like these from the printed numbers alone, so there is never a shortage of places to begin. Keep the margin list up to date as you go; it does much of the job of full pencil marks in far less space.

How do you print 12×12 Sudoku so it stays readable?

• Print only the pages you need. Puzzle n is on page n ÷ 2 + 1, rounded up, and its solution on page n ÷ 4 + 51, rounded up. Puzzle 37 is on page 20 and its solution on page 61.
• Letter or A4 both work. The pages are US Letter, but the grids sit well inside 0.6 in side margins, so printing on A4 at actual size crops nothing.
• Keep the scale at 100%. A 9 mm square has room for a number or a few small marks, not all twelve. Printing two pages to a sheet leaves too little room to write.
• Write 10, 11 and 12 small. A two-digit number written large spills toward the next square, where its 1 can be misread as a number of its own.

Can you use these PDFs with a class or group?

Yes, and the layout helps. Print pages 2 to 51 for the group and keep pages 52 to 76 back. Every puzzle has its number above the grid, so “Puzzle 14” means the same sheet for everyone, and with two puzzles to a page, one printed page cut in half does for two solvers.

Match the level to what has been taught. On Easy and Medium, singles finish every puzzle, so nobody meets a step they have not learned. Hard is mixed, half its puzzles needing more, which suits a puzzle club better than a lesson. For a group that has never seen a rectangular box, a printable 6×6 sheet shows the same idea first, with 2×3 boxes.

How do you check your answers?

Turn to the solutions at the back and find the same puzzle number. Because every puzzle has exactly one answer, any square that differs from the key is a mistake, never a second solution. Compare a box at a time rather than reading across the page: twelve boxes of twelve squares are easier to keep track of than 144 loose ones.

If you are stuck halfway and want to know whether what you have written so far is right, without seeing the whole answer, cover the key with a sheet of paper and uncover one row at a time. Or type your grid into the solver, with A, B and C for 10, 11 and 12: if it reports no solution or a repeated number, something you wrote is wrong.

For more without a printer, the online game deals new puzzles from the same generator at all four levels. The printable 16×16 set is the next size up, and every other set is in our printable sudoku collection.