Ebooks & reading technology
Why Two Ebook Editions of One Book Have Different Page Counts
The number on the cover of an ebook is not a measurement of the book. It is a conversion of a fixed-format assumption, and understanding how it is made explains a number of confusing comparisons.
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If a book is 300 printed pages, why is one ebook 240 pages and another 520? This comes up constantly in reviews and it confuses readers, so it is worth explaining properly.
An ebook page is a fiction
An ebook is a stream of text with no fixed page geometry. A reading device decides line length, type size, margins and spacing based on the screen. Change any of those and the pagination changes completely. A page count in an ebook is therefore not a measurement of the same thing a printed page count measures.
How the number is produced anyway
Publishers and retailers still display one, usually generated by a specific reading system at a specific font size on a specific device. Change the system and the number changes. This is why the same file can show different page counts on different services, and it is not a bug in either.
Reflowable versus fixed layout
A reflowable EPUB re-lays-out for the reader's device, so its displayed page count depends on the device. A fixed-layout EPUB is already paginated, so its count is stable and represents real pages. This is the main reason two editions of one novel can differ so widely.
What the number is actually good for
Estimating reading time, and that is genuinely useful: most readers move at a fairly consistent rate for prose. It is a poor basis for comparing the length of two books, especially across formats, and a very poor basis for comparing two editions of the same book, since any difference is a property of the format rather than the writing.
What the number is actually for
Treat an ebook page count as roughly one and a quarter times the printed page count for typical prose, recognise that it moves, and do not draw conclusions from it about whether a book is long.