Long edge for normal portrait documents. The page turns like a book and both sides read upright.
Short edge only for documents that flip like a notepad, which mostly means landscape pages. Choosing it on a portrait document is what makes every second side upside down.
Double-sided printing halves your paper and introduces exactly one confusing decision. The setting is usually called binding edge or flip on, and the two options are named after which edge of the paper the page turns on.
What long and short edge mean
A sheet of A4 in portrait has two long edges down the sides and two short edges along the top and bottom. The setting is telling the printer which of those the reader will turn the page around.
Turning on a long edge is what a book does: you grip the right-hand side and swing it left, rotating around the vertical edge. For that to work, the content on the back must be printed the same way up as the front.
Turning on a short edge is what a notepad does: you flip the sheet upwards, rotating around the horizontal edge. For that to read correctly, the back has to be printed upside down relative to the front.
- Portrait report or letterLong edge
- Portrait bound documentLong edge
- Landscape slides or tablesShort edge
- Calendar flipping upwardShort edge
- Anything you are unsure aboutLong edge
When the printer cannot duplex
Many printers have no automatic duplex unit, and manual double-siding is entirely workable once you know the sequence. Split the document into odd and even pages, print one set, turn the stack over, print the other.
Extract the odd pages and print them
Pages 1, 3, 5 and so on. Most print dialogs offer an odd pages only option, and splitting the document works just as well and gives you a file you can reprint if the second pass goes wrong.
Turn the stack over without reordering it
This is the step that decides everything. Take the printed stack, flip it as a block, and put it back in the tray. Do not shuffle or reverse it yet.
Print the even pages, reversed if needed
Pages 2, 4, 6. Whether this set needs reversing depends on whether your printer delivers pages face up or face down.
Face up or face down
The complication in manual duplex is that printers differ in how they stack output. Some deliver pages face up, which leaves the stack in reverse order. Others deliver face down, which keeps it in order.
This decides whether the even pages need printing in reverse. If your printer stacks face up, the last odd page is on top, so the even pages must be sent in reverse order to match. If it stacks face down, normal order is correct. The four page test settles it in under a minute.
Booklet printing is different
Booklet or saddle-stitch printing is not the same operation, though the settings sit next to each other. It prints two pages side by side on each side of a sheet, arranged so that folding the whole stack in half produces a readable booklet.
The page ordering for that is genuinely complicated: on an eight page booklet, the first sheet carries pages 8 and 1 on one side and 2 and 7 on the other. The print dialog calculates this, which is why it is worth using the booklet option rather than trying to assemble the order by hand.
Before printing the whole thing
Double-sided faults waste twice the paper of single-sided ones, and they are entirely avoidable with one test.
Print four pages first. It costs two sheets and tells you whether your binding edge and flip direction are right.
Check the page count is even. If it is odd, decide deliberately what happens on the last back rather than discovering it.
Watch for mixed orientation. A landscape table among portrait pages needs its own binding edge, which one global setting cannot provide.
Split odd and even pages
For printers without duplex. Pull out the odd pages, then the even ones, in your browser.
Common questions
Getting both sides the right way up.
01Why are the backs of my pages upside down?
The binding edge is set to short edge on a portrait document. Short edge is for pages that flip upward like a notepad, and it deliberately prints the reverse side inverted. Switch to long edge.
02What is the difference between long edge and short edge?
They describe which edge the reader turns the page around. Long edge is the book-style turn used by almost every portrait document. Short edge is the notepad-style upward flip, which suits landscape pages.
03How do I print double-sided without a duplex printer?
Print the odd pages, turn the stack over as a block, then print the even pages. Whether the even set needs reversing depends on whether your printer stacks face up or face down, which a four page test will tell you.
04Should I reverse the even pages?
Only if your printer delivers pages face up, which leaves the stack in reverse order. Printers that deliver face down keep it in order and need no reversal. Test with four pages to find out which yours does.
05What happens with an odd number of pages?
The final sheet prints on one side only. That is usually fine, though if the document will be bound with others, adding a deliberate blank final page avoids anyone thinking a page is missing.
06Is booklet printing the same as double-sided?
No. Booklet printing places two pages side by side on each side of a sheet and orders them so that folding the stack produces a readable booklet. The page ordering is complex enough that the print dialog should calculate it for you.