Guide
EPUB vs PDF: which format to use, with a real size test
EPUB vs PDF comes down to layout. An EPUB's text reflows to fit any screen and any font size, so it suits reading on a phone or e-reader. A PDF locks every page in place, so it suits printing and anything whose design has to stay exactly as made.
Neither format is better in general. They solve different problems, and the same book can be a joy in one and a chore in the other. Below is how they differ, what we measured on three public-domain books, and how to pick.
How the two formats differ
| EPUB | ||
|---|---|---|
| Layout | Flows to fit the screen | Fixed pages |
| Changing the type size | Text rewraps, as large as you like | You zoom, then scroll sideways |
| Your own font, night mode | Yes, in most reading apps | Rarely |
| Page numbers | Change with the screen, unless the book carries print page marks | The same for every reader, so easy to cite |
| Printing | Awkward | Made for it |
| Forms and signatures | No | Yes |
| Complex design | Simplified by the reading app | Kept exactly |
| Standard | Open, kept by the W3C | Open, ISO 32000 |
The same book in both formats: what we measured
We turned three public-domain EPUBs into PDFs with our converter on Letter-size pages, in November 2026, and compared the files. The PDFs carry page numbers, running heads and a contents page.
| Book | EPUB | PDF pages | Words kept in the PDF | |
|---|---|---|---|---|
| Alice's Adventures in Wonderland | 185 KB | 609 KB | 96 | 99.9% |
| Frankenstein | 430 KB | 1,227 KB | 210 | 100% |
| Pride and Prejudice (Standard Ebooks) | 812 KB | 2,063 KB | 341 | 100% |
For plain text, the PDF came out 2.5 to 3.3 times the size of the EPUB, and the words were the same. Neither format keeps more of the book than the other. The difference is entirely how it reaches your eyes: a 96-page Letter-size PDF on a phone is 96 pages of small type, while the EPUB simply fills the screen at the size you choose.
Scans go the other way round. A scanned PDF is pictures of pages, and an EPUB made from those pictures can't reflow at all. It needs its text read first, which is what converting a scanned PDF involves.
Which one to choose
Choose EPUB for novels, memoirs, long reports and anything mostly made of text that you'll read on a phone, tablet or e-reader. It also suits readers who need larger type, and screen readers, which follow an EPUB's headings and reading order more reliably than a page layout.
Choose PDF for anything that will be printed, signed or cited by page: contracts, forms, sheet music, posters, and textbooks and magazines whose layout carries meaning. Send a PDF when everyone must see exactly the same page.
Have the wrong one? Both directions are free here: PDF to EPUB rebuilds paragraphs, chapters and tables from the page layout, and EPUB to PDF sets a book up for printing with page numbers and a contents page. If your EPUB is headed for an Amazon device, sending EPUB to a Kindle takes no conversion at all. Weighing EPUB against Amazon's older format instead? See EPUB vs MOBI.
Questions
Is EPUB better than PDF?
For reading on a phone or e-reader, usually yes, because the text reflows to the screen. For printing, forms and fixed design, PDF is better. Neither keeps more of the words: in our test both held the same text.
Is EPUB smaller than PDF?
For plain text, yes. Our three test books came out 2.5 to 3.3 times larger as PDFs. A book full of pictures can go either way, since the pictures take up most of the space in both.
Is PDF an open standard?
Yes. PDF is published as ISO 32000, and EPUB is an open standard kept by the W3C.
Can a Kindle read EPUB?
Through Send to Kindle, yes: Amazon converts the file on delivery. A Kindle can't open an EPUB copied over USB.
How do I open an EPUB file?
Apple Books on iPhone, iPad and Mac opens EPUB directly, Google Play Books takes uploads, and Kobo and Nook e-readers read it natively. To open one on any computer without a reading app, convert it to PDF.
Kindle is a trademark of Amazon.com, Inc. epubwise is not affiliated with Amazon.