The Ebook Doctor Mailbag – Epub and Pdf – the differences.

Since the introduction to the new series we have received a number of questions about the process -most will be covered over the coming weeks but since this was in one of the comments I decided to do a post. Dr. Sweety Shinde asked this question this morning and since it is a question that comes up quite frequently David has put together an overview.

I am still old school of thought – preferring the paperback version to Kindle. However, I do doff my hat at evolution. Could you clarify the difference between ePub and pdf version? Are they really different? Goodreads asks for ebook in ePub version, while excerpts can be in pdf version.


Although both Epub and PDF formats can be read by most Ebook readers they are completely different formats and each delivers the content in a completely different way.


PDF is a format originally developed for printed documents. One of its most important characteristics is that it maintains the layout, formatting, fonts, page size, margins, etc. exactly as the designer intended regardless of the viewing device. The Fonts to be used are Embedded in the PDF file so that the appearance remains exactly as the designer intended.

If the screen is Zoomed in the fonts and images will appear bigger but it is the same as looking at printed text through a magnifying glass, the part outside the zoomed area disappears off the edge of the screen and you have to drag the document around to see all the page.


The EPUB format was introduced in 2007 as a format to enable viewing of electronic documents in a completely different way.

Simply put, the Ebook is a ‘packaged’ website, and an E-reader is a hand-held web browser.

The Ebook contains a series of connected web pages which can be displayed using a browser. The pages are stored inside a “Package” or “Container”. For EPUB this has the .epub file extension.

What is very different with Ebooks is that they are designed to be “Reflowable”. The text size and fonts do not come from the EPUB file itself but, just like on a computer, the available fonts are stored on the E-reader and the user can choose the default font type, font size, page margins etc.

When a user zooms in the text reflows to fill the screen by changing the display font. The layout is not fixed and is in the control of the viewer.

An Epub file is not normally intended for printing and would give very strange results if printing is attempted as it is written in HTML and all the code would print.


  • You can produce a PDF from many different programs as the specification has been around for many years and is very well known.
  • Producing an EPUB is a rather different story as the file has to be formatted in very specific ways so that it can be displayed on any one of the possible display device available today.
  • An EPUB is a lot friendlier than PDF for viewing on a variety of devices with different screen sizes: phones, E-readers, tablets, PCs and MACS because it can be set to fill the screen with text at a comfortable size and it is easy to flick through pages.
  • If you have ever tried to read a PDF on a phone you will know that navigation is a nightmare.
  • EPUBS are great for narrative text (Mainly fiction) and are friendly to use. But currently they are no good for complex books that have lots of formatting, images, equations etc. (Mainly Non-fiction).

PDFs are great for complex layouts as it is a static format and nothing changes. The layout is designed to communicate the content effectively. To achieve the same in an EPUB is currently very difficult mainly because there are so many different devices all configured differently and each producing its own unique display.

  • One big disadvantage of PDFs is that you cannot distribute them via Amazon. They want everything in their own proprietary Kindle format (Reflowable like EPUB) so all files have to be converted to suit. Unfortunately this is not always easy as a complex PDF will not usually convert into a coherent Ebook.
  • The EPUB format is probably the most common of all the new Ebook formats and is widely supported across all platforms. Most E-readers like Apple’s iBooks, Barnes & Noble’s Nook, Kobo, Adobe Digital Editions, Aldiko on Android among others (nearly 300) support .EPUB files.

Many E-book retailers have “Look Inside” available and since this is normally available on a computer screen it generally uses “snapshots” from the book, but in a Fixed not Reflowable format. Thus they can use a PDF file to provide the look inside feature even though they are not selling the PDF.


©DavidCronin – 2015.