Ebook Format Comparison — EPUB, MOBI, AZW3, PDF, and More
Every ebook format explained — features, device support, DRM, reflowable vs fixed layout, and which format to choose for reading, publishing, or converting.
The ebook format landscape is a mess. Amazon uses their own formats, Apple and Kobo use EPUB, PDFs work everywhere but aren't really ebooks, and there are half a dozen legacy formats still floating around. Here's the definitive breakdown.
The Comparison Table
| Format | Reflowable | DRM Support | Primary Platform | Image Support | Audio/Video | Open Standard |
|---|---|---|---|---|---|---|
| EPUB 3 | Yes | Optional (Adobe DRM) | Kobo, Apple Books, Google Play | Yes | Yes | Yes (W3C) |
| AZW3 (KF8) | Yes | Amazon DRM | Kindle | Yes | Limited | No (Amazon proprietary) |
| MOBI | Yes | Amazon DRM | Older Kindles | Basic | No | No (legacy) |
| No (fixed layout) | Optional | Universal | Yes | No | Yes (ISO 32000) | |
| AZW | Yes | Amazon DRM | Older Kindles | Basic | No | No (legacy) |
| DJVU | No | No | Academic/archival | Optimized for scans | No | Yes |
| CBZ/CBR | No | No | Comic readers | Yes (primary content) | No | Yes (ZIP/RAR archives) |
| FB2 | Yes | No | Russian-language readers | Yes | No | Yes |
| LIT | Yes | Microsoft DRM | Discontinued | Yes | No | No (dead) |
EPUB: The Standard
EPUB is the open standard maintained by the W3C. Under the hood, it's a ZIP archive containing XHTML content, CSS stylesheets, images, and metadata. EPUB 3 supports JavaScript, audio, video, and complex layouts.
Every major reading platform except Amazon supports EPUB. Apple Books, Kobo, Google Play Books, Barnes & Noble Nook — they all use EPUB as their native format.
If you're self-publishing or distributing ebooks outside of Amazon, EPUB is what you want.
Kindle Formats: AZW3 and the MOBI Legacy
Amazon developed their own format ecosystem. MOBI was the original Kindle format, now effectively replaced by AZW3 (also called KF8, Kindle Format 8). AZW3 supports more advanced formatting — CSS, embedded fonts, SVG — making it closer to EPUB 3 in capability.
In 2024, Amazon stopped accepting MOBI uploads for Kindle Direct Publishing, requiring EPUB or DOCX instead. They convert to their internal format automatically. So even for Kindle, you can start with EPUB.
Send to Kindle now accepts EPUB files directly, which was a long-awaited change.PDF: Not Really an Ebook Format
PDFs work on every device, but they're a poor ebook experience. The text is fixed — it doesn't reflow to fit your screen size. On a phone, you're constantly pinching to zoom and scrolling sideways. Font size can't be adjusted. Night mode depends on the reader app.
PDFs are great for documents that need exact layout preservation: academic papers, forms, brochures, manuals with specific page designs. But for reading a novel on your phone? Use EPUB.
That said, some academic publishers distribute only in PDF. If you need to convert a PDF to EPUB for a better reading experience, the results depend heavily on the PDF's structure. Simple text-heavy PDFs convert well; complex multi-column layouts with figures are harder.
Reflowable vs Fixed Layout
Reflowable means the text adapts to the screen. Bigger phone? More words per line. Increase font size? Text reflows to fit. This is how most ebooks work and how most readers prefer it. Fixed layout means each page looks exactly the same regardless of screen size. Children's picture books, cookbooks with precise image-text placement, and comics use fixed layout because the visual arrangement is part of the content.EPUB supports both modes. PDF is always fixed layout.
Which Format to Choose
Reading on Kindle: Send EPUB directly via Send to Kindle, or use Amazon's EPUB upload for KDP publishing. Reading on Apple/Kobo/Nook: EPUB. Self-publishing everywhere: Create in EPUB, let each platform convert as needed. Academic papers and formal documents: PDF. Comics and manga: CBZ (it's just a ZIP of images in order — dead simple and universal among comic readers).Converting Between Formats
MyPDF's ebook converter handles conversions between EPUB, PDF, MOBI, and other document formats. Upload your file and pick your target format.Related Tools
- Convert to EPUB — Transform documents into EPUB ebooks
- EPUB to PDF — Convert ebooks to PDF for printing
- PDF to Word — Extract text from PDFs for ebook creation