Why an EPUB looks wrong when you just print it

You have an EPUB. You want it on paper. The obvious move is to open it in whatever app you read in and hit print. The result is almost always disappointing in the same handful of ways.

What you get instead of a book

Enormous type. Reading apps print what is on screen, and what is on screen is sized for reading at arm’s length on a backlit display. Transferred to A4 it comes out at something like 16 or 18pt, which on paper reads as a large-print edition nobody asked for. A 300-page novel becomes 600 pages.

Margins from the screen, not the page. The app was leaving room for your thumbs. A printer needs room for a binding, or at least room that does not look like a mistake. These are different amounts in different places, and the app has no idea it is now making a physical object.

No page numbers, or the wrong ones. An EPUB has no pages, so the app either prints nothing or prints its own invented “location” numbers, which mean nothing once the file is on paper and correspond to nothing anybody else would see.

A table of contents that does not work. If it prints at all, it is a list of chapter names with no page numbers next to them, because at the moment it was written there were no pages to number.

Chapters starting halfway down a page. Reading apps flow continuously by design; that is the whole point of a reflowable format. Paper wants a chapter to begin at the top of a fresh sheet.

Hyperlinks printed as blue underlined text. Every cross-reference, every footnote marker, every URL in the endnotes, rendered in blue and underlined on a black-and-white page. On screen it signals “tap me”. On paper it’s just noise, and on a mono laser it comes out as grey.

Images at whatever size the screen suggested. A diagram sized to fill a phone column gets printed at that width on A4, marooned in the middle of the page with three inches of white either side.

Why this is not the app’s fault

None of that is a bug. It is the format doing exactly what it was designed to do.

An EPUB is a zip full of HTML with no page size, no page count and no fixed line breaks. The reading app invents all of that, fresh, every time you open the book, from your screen and your chosen font. That is why the same novel shows 312 pages on your phone and 190 on a tablet: neither number is in the file, because there is nothing in the file to count.

When you print from that app, you are asking it to commit its on-screen guesses to paper. It obliges, because that is the only thing it knows how to do.

It’s worth sitting with how strange this is compared to every other document you own. A Word file knows it’s A4. A PDF knows exactly where every character sits. An EPUB knows neither, on purpose, because knowing would stop it working on a watch and a 27-inch monitor at the same time. The flexibility that makes it a good ebook format is precisely what makes it a bad printing format.

The page-count question

This is the clearest demonstration. Open the same EPUB on a phone and on a tablet and look at the page count. They won’t match, and neither will match the paperback. There is no correct answer, because the number isn’t stored anywhere. It’s computed fresh from your screen size, your font choice and your type size, every time you open it.

Which is also why an EPUB can’t have a contents page with page numbers in it. There are no page numbers to write down. The book’s own table of contents is a list of links to positions in the markup, and it works perfectly on screen for exactly that reason.

What converting properly does differently

The conversion has to make the same decisions the app was making, but for paper instead of for a screen, and it lets you choose:

• A real page size. A4 or Letter, so the type is set for a sheet of paper rather than scaled onto one afterwards.
• A real type size. 11pt is a book. You pick it, once, up front.
• Real page numbers, and a contents page whose numbers point at them.
• Chapters starting on fresh pages, because paper is not a scroll.
• Justified text with a straight right edge, which is what a printed book looks like and what a reflowing screen usually cannot manage.
• Running heads, the chapter title along the top, so you know where you are in a stack of loose sheets.

None of this is clever. It is the set of decisions that has to be made when something stops being able to reflow, made on purpose rather than inherited from a screen.

There’s a fuller account of each choice in choosing a page size and margins, and a page on what the navigation furniture is for in EPUB to PDF with page numbers.

Why “print to PDF” doesn’t help

The obvious workaround is to print from the reading app to a PDF file rather than to paper, then print that. It doesn’t fix anything, and it’s worth understanding why, because a lot of people try it and conclude the problem is unfixable.

Printing to PDF captures the app’s on-screen guesses into a file. The type is still 16pt, the margins are still the app’s, the page numbers are still absent. You’ve changed the container without changing any of the decisions inside it. The PDF is now a faithful record of a bad layout.

Converting is different because it goes back to the markup and lays it out again from scratch, for the page size you asked for. The app never gets a vote.

Doing it properly, in order

1. Check the file will convert. DRM-protected books stop here. Where to find EPUBs that will actually convert covers how to tell, and what to do about it.
2. Pick the page size to match your paper. A4 nearly everywhere, US Letter in the US and Canada. This is a fact about your printer, not a preference.
3. Pick a type size. 11pt is a book. Print two pages at it before committing.
4. Leave the contents page and page numbers on. They’re the entire reason to do this rather than printing from the app.
5. Set the print dialog to Actual size. See below.
6. Print pages 3 and 4 first. Two sheets tell you nearly everything two hundred would.

The one thing to check before printing

Set your print dialog to Actual size or 100%, not “Fit to page”. Printers can’t print to the very edge of a sheet, and “fit to page” shrinks everything by a few per cent to stay inside that border, which quietly undoes the margins and type size you just chose. It’s the single most common reason a carefully made PDF prints looking slightly off.

The tell is that everything looks fine, just a bit small and a bit too generously margined, and you can’t quite say why. If that’s what you’re seeing, it’s the scaling setting rather than the file.

If you want an object rather than a stack

Printing A4 one-sided gives you a pile of paper. That’s fine for something you’ll read once and recycle. If you want it to survive being carried about, fold it: printing an ebook as a folded booklet covers A5 pages, folded A4 sheets and the page-count arithmetic that catches everyone the first time.