EPUB vs PDF vs MOBI: which should you use?
What each ebook format is good at, how they differ, and which one to pick for reading, printing or Kindle. Updated October 28, 2026.
Most ebooks come in one of three formats. They are not interchangeable: each one was built for a different job. Here is how they compare and when to use each.
| EPUB | MOBI | ||
|---|---|---|---|
| Layout | Reflowable | Fixed pages | Reflowable |
| Made by | Open standard (W3C) | Adobe, now an ISO standard | Amazon (legacy) |
| Best on | Phones, tablets, e-readers | Computers, printing | Older Kindles |
| Reader can change font size | Yes | No | Yes |
| Prints well | No | Yes | No |
| Kindle | Via Send to Kindle | Yes, fixed pages | USB only on older models |
| Status | Current standard | Current standard | Being phased out |
EPUB: the standard for reading
EPUB is the open format used by almost every ebook store and reading app except Amazon’s own store. Text reflows to fit the screen, and readers choose the font, size and colors. It is the best choice for novels and any long reading on a phone or e-reader.
PDF: the standard for fixed layouts
A PDF looks exactly the same on every device, which makes it ideal for printing, forms, design-heavy books, and sending a document to someone who has no ebook app. On a small screen, though, you will be zooming and scrolling. Convert EPUB to PDF when you need to print or share; convert PDF to EPUB when you want to read comfortably on a phone.
MOBI: Amazon’s legacy format
MOBI was the format of early Kindles. Amazon now uses newer formats, and Send to Kindle no longer accepts MOBI files. If you have old MOBI books, convert them to EPUB so they keep working everywhere. Only convert to MOBI if you load books onto an older Kindle by USB.
Quick decision guide
- Reading on a phone, tablet or e-reader: EPUB
- Printing or sharing an exact layout: PDF
- Reading on a current Kindle: send an EPUB with Send to Kindle (how)
- Loading an older Kindle by USB: MOBI
Frequently asked questions
Which ebook format is best?
For reading on phones and e-readers, EPUB. For printing and sharing an exact layout, PDF. MOBI is only worth using for older Kindles loaded by USB.
Is MOBI still used?
Rarely. Amazon has moved to newer formats and Send to Kindle stopped accepting MOBI in 2022. EPUB is a better choice for nearly everyone.
Can I convert between these formats?
Yes, as long as the files are DRM-free. See our ebook converters.