Print a PDF as a folded booklet
A booklet maker rearranges PDF pages into saddle-stitch imposition order and places them two-up on landscape sheets, so that a duplex-printed stack, folded down the middle, reads as a normal booklet. This tool pads your document to a multiple of four with blank pages, builds the imposed sheets, and hands back a print-ready PDF — print it double-sided with flip on the short edge, fold, and optionally staple along the crease. Everything runs in your browser.
How it works
Fold a stack of sheets in half and each sheet suddenly holds four booklet pages: two on its front, two on its back. That geometry dictates everything. Because pages come in fours, the tool first pads your document with blank pages up to the next multiple of four — a 18-page zine becomes 20, a 21-page program becomes 24. The blanks are appended at the logical end, which after folding lands them harmlessly at the back of the booklet or around the center spread.
Next comes the imposition — the reordering that printers have done since the hand-press era. For a padded page count n, the outermost sheet must show the covers: its front carries page n on the left and page 1 on the right (so page 1 faces up when folded), and its back carries page 2 on the left and page n − 1 on the right. The next sheet repeats the pattern one step in: front n − 2 | 3, back 4 | n − 3. In general, sheet k (counting from 1) holds the four pages n − 2k + 2, 2k − 1, 2k, n − 2k + 1 — the sequence closes in from both ends until the two middle pages meet face-to-face on the innermost sheet. For n = 8 the full order is 8,1 | 2,7 | 6,3 | 4,5.
Mechanically, the tool builds each output sheet as a new landscape page and embeds the source pages as form XObjects — self-contained bundles of a page's content stream and resources. Each XObject is drawn with a transformation matrix that scales it to fit half the sheet and translates it to the left or right slot. Nothing is rasterized: text remains vector text, at roughly 70% linear scale (each half of a landscape A4 sheet is exactly A5).
The short-edge instruction is not a preference but a consequence of the landscape orientation. Duplex printers offer two ways to flip the paper for side two; on a landscape sheet, only flipping about the short edge keeps the back printed the same way up as the front. Choose long-edge by mistake and every back side of your booklet comes out upside down — the single most common booklet-printing failure.
Worked example: an 18-page zine on five sheets of A4
An 18-page A5-formatted zine (2.6 MB) goes in. The tool pads it to 20 pages with two blanks, producing 10 landscape A4 output pages — five physical sheets once printed duplex. The imposed order is:
Sheet 1: front 20 | 1, back 2 | 19 · Sheet 2: front 18 | 3, back 4 | 17 · Sheet 3: front 16 | 5, back 6 | 15 · Sheet 4: front 14 | 7, back 8 | 13 · Sheet 5: front 12 | 9, back 10 | 11.
Pages 19 and 20 are the padding blanks, which end up as the inside and outside of the back cover — invisible in practice. The output PDF is 2.7 MB (the reordering adds only sheet structure). Printed on five sheets of A4, duplex, short-edge flip, 100% scale, the stack folds into a 20-page A5 booklet where page 10 faces page 11 at the center spread — exactly where the innermost sheet's back has them side by side.
Frequently asked questions
How do I print a PDF as a foldable booklet?
Run the PDF through the tool above, then print the output double-sided with flip on short edge selected and scaling set to 100%. Fold the printed stack in half down the middle and the pages read in order.
Why must a booklet's page count be a multiple of four?
Every folded sheet contributes exactly four booklet pages — two on the front and two on the back. The tool pads the document with blank pages up to the next multiple of four, and the blanks end up around the middle fold or at the end.
Why do I have to flip on the short edge when printing a booklet?
The output sheets are landscape, and short-edge flipping keeps the back of each sheet upright relative to the front. With long-edge flipping, alternating pages print upside down after folding.
What order are the pages placed in for saddle-stitch printing?
For a padded count n, the first sheet's front carries page n on the left and page 1 on the right; its back carries page 2 on the left and page n minus 1 on the right. Each following sheet repeats the pattern working inward until the two middle pages meet on the innermost sheet.
Are the pages shrunk when they are placed two per sheet?
Yes, necessarily: two portrait pages share one landscape sheet of the same paper size, so each is scaled to about 70% linear size — A4 content becomes A5, Letter becomes half-Letter. Vector text stays sharp because the scaling is mathematical, not rasterized.
How large a booklet can I make this way?
Saddle stitching works well up to roughly 60 booklet pages (15 sheets); beyond that the folded stack creeps outward and refuses to lie flat. For longer documents, split them into sections and fold each separately.