Quick Verdict
Use PDF when…
Use PDF for documents where exact layout matters — reports with charts, contracts, technical drawings, photo books, comic books. PDF is also superior for printing.
Use MOBI when…
Use MOBI (or EPUB) for novels, narrative text content, and any reading material where the experience benefits from text reflow, adjustable fonts, and bookmarking.
PDF vs MOBI: Feature Comparison
| Feature | MOBI | |
|---|---|---|
| Layout | Fixed | Reflowable |
| Adjustable text size | Limited | Yes (any size) |
| Kindle native support | Limited (Send to Kindle) | Native |
| iPad/iPhone reading | Books app supports it | Kindle app required |
| Image fidelity | Excellent | Lossy |
| DRM common | Sometimes (form/signed PDFs) | Yes (Amazon Kindle DRM) |
When PDF wins
- ✓Layout: Fixed
- ✓Adjustable text size: Limited
- ✓Kindle native support: Limited (Send to Kindle)
When MOBI wins
- ✓Layout: Reflowable
- ✓Adjustable text size: Yes (any size)
- ✓Kindle native support: Native
Frequently asked questions
Should I send a friend a book as PDF or MOBI?
MOBI for Kindle users (or EPUB for non-Kindle e-readers). PDF only if the layout is critical — e.g., a comic book, a magazine, a technical document with diagrams. For novels, MOBI/EPUB is dramatically better for reading on small screens.
How do I convert PDF to MOBI?
Use Calibre (free): add the PDF, click Convert books, select MOBI as output format. The conversion attempts to reconstruct text flow from PDF's layout — results are good for text-heavy PDFs and poor for image-heavy or multi-column PDFs.
Ready to convert?
Free, browser-based converters — no upload, no signup required.
More comparisons
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