You've got a 20-page document you want to print as a folded booklet — 5 sheets of A4 folded in half, stapled at the spine. The catch: page order in a booklet isn't 1, 2, 3, 4. Page 1 prints next to page 20. Page 2 prints next to page 19.
Printing software handles the math if you give it the right settings.
Get the page count right
Booklets need a page count divisible by 4. A 20-page document fits exactly. A 19-page document needs a blank page added at the end.
Insert a blank page if needed. Then your booklet has the right number of pages for folding.
Use the print dialog's booklet mode
In Adobe Reader, Print → Booklet. In Preview, Print → Paper Handling → Two-Sided + Booklet. The print software reorders pages automatically.
Result: each sheet has two pages on each side, in the right order so folding produces a readable booklet.
Test on one sheet first
Print just the first and last sheet of the booklet. Fold them. Check that pages 1, 2, 3, 4 land where expected.
If the order is wrong, your printer might be doing duplex weirdly. Try "Short edge binding" vs "Long edge binding" in the dialog.
FAQ
What if my document has more pages than I can fold?
Most home printers handle 20-page booklets fine. Beyond that, split into multiple booklets or use a commercial shop.
Should I add bleed for the cover?
For home printing, no — bleed requires trimming after print. For commercial, yes if the cover has full-bleed art.
Can I print booklets on Letter paper?
Yes — booklet mode adapts to the paper size. Letter folded gives a smaller booklet than A4 but works the same.
What if pages come out upside down?
Your printer's duplex orientation is set wrong. Toggle long-edge vs short-edge binding in the print dialog.
Booklet printing is software's job, not yours. Use your printer's booklet mode and prepare the PDF beforehand with Flint's editor.