What is the difference between VitalSource ePub and PDF formats?

Here's a breakdown of the key differences between the two formats:

ePub (Reflowable Text) ePub titles are reflowable, meaning the text automatically adjusts to fit the size of your screen and allows you to change the font size for comfortable reading. These books conform to ePub 3 industry standards and can include interactive features such as links, quizzes, and embedded videos. This makes ePub a great choice for reading on smaller screens like phones and tablets.

PDF (Page-Fidelity) PDF titles maintain the look and feel of the print book — the layout is fixed and does not change based on your screen size. You can zoom in, but the font size cannot be adjusted. PDFs are better suited for books with complex layouts such as charts, tables, illustrations, and high-quality images, and are most comfortable to read on larger screens like laptops and desktops.

Both formats can be read with screen readers such as JAWS and NVDA, and both support VitalSource's built-in text-to-speech features. However, when zooming in, ePub text will reflow to fit the screen while PDF text will not — this is a limitation of the PDF format itself. If you're unsure which format is right for you, ePub is generally the better choice for everyday reading on any device, while PDF is preferable if you need the content to match the printed textbook exactly.