E-books and documents mostly come in two formats: EPUB and PDF. They can hold the same text, but they behave very differently. Choosing the wrong one leads to familiar frustrations: tiny unreadable text on a phone, or a book whose layout falls apart when printed. This guide explains the real difference between the two and when to use each.
The core difference: reflowable versus fixed
EPUB is reflowable
An EPUB is like a small website packaged into one file. Text is stored as paragraphs and headings, not as positioned lines on a page. Your reading app decides how to lay it out: it wraps lines to fit your screen, uses your chosen font and size, and paginates on the fly. Change the font size and the whole book rearranges itself.
PDF is fixed
A PDF stores pages exactly as designed. Every line, image and margin is in a fixed position. It looks the same on every device and when printed. Zooming makes everything bigger, but lines do not rewrap.
When EPUB is better
- Reading on phones and small tablets. Text fits the screen at any size, with no sideways scrolling.
- Long-form reading. Novels, non-fiction and long reports are more comfortable when you can choose font, size, spacing and colour themes.
- Accessibility. Readers who need large text, high contrast, a dyslexia-friendly font or screen reader support benefit from reflowable text.
- E-reader devices. Many e-readers are built around reflowable formats like EPUB.
When PDF is better
- Printing. Pages come out exactly as they look on screen.
- Layout-heavy documents. Magazines, brochures, forms, technical drawings, academic papers with complex figures and anything where design matters.
- Citing page numbers. Everyone sees the same page numbers.
- Official documents. Contracts, invoices and certificates are expected to look identical for everyone.
- Sharing with anyone. Almost every device can open a PDF without installing anything.
Converting between them
Because the formats work so differently, converting is not a simple copy. It is a translation, and some things change.
EPUB to PDF
The EPUB to PDF converter lays the book out on fixed pages. You choose A4 or US Letter and a text size from 9 to 16 points. Chapters become PDF bookmarks, images are placed in the text, and page numbers are added. The book is typeset in clean, readable fonts rather than the publisher's styling, so fonts and decorative design change.
PDF to EPUB
The PDF to EPUB converter reads the text on each page and rebuilds paragraphs, headings and chapters, removing repeated headers, footers and page numbers. The result reflows on any screen. Images, tables and multi-column layouts do not carry over well, so PDF to EPUB works best for text-heavy documents with a single column.
Things neither format can fix
Scanned documents
A scanned PDF is a set of pictures of pages, with no real text inside. It cannot be reflowed into an EPUB without text recognition, which is not currently offered.
DRM-protected books
E-books with digital rights management are encrypted for specific apps. Our converters do not remove DRM and will tell you if a book is protected. DRM-free books convert normally.
A quick decision guide
- Reading a novel on your phone? EPUB.
- Printing a chapter for a class? PDF.
- Sending a report that must look the same for everyone? PDF.
- Reading a long text-only report on the train? Convert the PDF to EPUB.
- Creating large-print copies? EPUB with large text, or PDF at 14 to 16 points if it must be printed.
- A magazine or brochure? Keep the PDF.
Worked examples
A book club. Members read the same public domain novel on different devices. For discussion, the organiser converts the EPUB to PDF at 11 points so everyone can refer to the same page numbers.
A student's reading list. A student converts long, single-column PDF articles to EPUB to read comfortably on his phone, but keeps two-column papers as PDFs because they convert less cleanly.
An author's manuscript. An author exports her draft as EPUB for beta readers on e-readers, and as PDF for a printed copy her editor marks up by hand.
A short history of both formats
PDF was created in the early 1990s to solve a simple problem: documents looked different on every computer and printer. PDF captured pages exactly, so a document created on one machine looked identical everywhere. It became an open standard and is now the default for official documents worldwide.
EPUB grew out of efforts in the 2000s to create an open standard for e-books. Instead of copying printed pages, it embraced the web's approach: content that adapts to the screen. As phones and e-readers spread, reflowable reading became more important, and EPUB became the most widely used open e-book format.
Understanding their origins explains their strengths. PDF was born to look the same everywhere. EPUB was born to fit wherever you read.
Accessibility in more detail
Reflowable EPUB lets readers choose large text, change fonts, adjust spacing and use high-contrast themes, and it works well with screen readers because the text has a clear reading order. PDFs can be made accessible too, but only if they were carefully prepared with tags and reading order, which many are not. If you produce documents for a wide audience, offering both an EPUB and a PDF covers most needs.
Questions people ask
Can a PDF be made reflowable without converting? Some reading apps offer a "reflow" mode for PDFs, but results vary. Converting to EPUB gives a proper reflowable book.
Will my EPUB look the same as the printed book? No. Reading apps decide the layout, which is the point of EPUB.
Which format is smaller? It depends. Text-only EPUBs are usually small; PDFs with images and embedded fonts can be larger.
Which is better for accessibility? Generally EPUB, because text reflows and reading apps support many accessibility features.
In short
EPUB reflows to fit any screen and suits comfortable reading, especially on phones and e-readers. PDF keeps a fixed layout that suits printing, citing and official documents. Convert EPUB to PDF when you need fixed pages, and PDF to EPUB when you want to read text-heavy documents comfortably on a small screen.