PDF vs EPUB vs MOBI: Which Book Format Should You Use?
Choosing the right book format is crucial for reaching your readers. Each format serves a different purpose and platform. Here's what you need to know.
Quick Comparison
| Format | Best For | Appearance | Flexibility | Device Support |
|--------|----------|------------|-------------|-----------------|
| PDF | Print & Print-on-Demand | Fixed | Low (layout locked) | All devices |
| EPUB | E-readers | Responsive | High (adapts to device) | iPad, Android, Kobo, most e-readers |
| MOBI | Kindle (Legacy) | Responsive | Medium | Older Kindle devices |
PDF Format
What is PDF?
PDF (Portable Document Format) creates a fixed-layout document. Whatever you design appears exactly the same on every device.
Best For:
- Print books - Print-on-Demand (Amazon KDP Print, IngramSpark)
- Fixed-layout books - Coffee table books, heavily illustrated books, coloring books
- Document distribution - Contracts, technical documentation
- Universal compatibility - Works on any device with PDF reader
Advantages:
✅ Exact appearance - Looks identical on every device
✅ Print-ready - Professional print shops accept PDF
✅ Universal compatibility - Everyone can read PDF
✅ File security - Can encrypt, protect content
✅ Precise formatting - Perfect for complex layouts
✅ Good compression - Images compress well
Disadvantages:
❌ Not responsive - Text doesn't resize for small screens
❌ Poor mobile reading - Hard to read on phones
❌ Fixed margins - Can't adjust for device
❌ Not ideal for e-readers - Poor reading experience on Kindle
❌ Accessibility issues - Harder for screen readers
PDF Specifications:
- File size: Small (especially with compressed images)
- Margins: 0.75" to 1" (print) or 0.5" minimum
- Image resolution: 300 DPI (print) or 72 DPI (screen)
- Fonts: Can be embedded (important for distribution)
When to Use PDF:
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EPUB Format
What is EPUB?
EPUB (Electronic Publication) is a reflowable format that adapts to the device displaying it. Text and layout adjust automatically to fit screen size.
Best For:
- E-readers - iPad, Android tablets, dedicated e-readers
- Apple Books - Default format for Apple's store
- Most independent bookstores - Digital distribution
- Kobo, Google Play Books - Standard e-book format
- Accessibility - Best format for screen readers
Advantages:
✅ Responsive design - Automatically formats for any screen
✅ Better mobile reading - Text resizes for phones
✅ User control - Readers can adjust font size, colors
✅ Accessibility - Full support for screen readers
✅ Smaller file sizes - Compressed better than PDF
✅ Standard format - Most e-readers support EPUB
✅ Interactive features - Can include multimedia
Disadvantages:
❌ Unpredictable appearance - Looks different on each device
❌ Designer frustration - Less control over exact layout
❌ Not ideal for print - Images may not print well
❌ Image handling - Requires proper optimization
❌ Complex table layouts - Difficult to format tables
EPUB Specifications:
- File structure: ZIP container with XML files
- Responsive: Adapts to device screen size
- Images: 72 DPI screen resolution recommended
- File size: Varies, typically smaller than PDF
- Fonts: Can embed but adds file size
- Interactive: Supports audio, video, multimedia
When to Use EPUB:
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MOBI Format
What is MOBI?
MOBI (Mobipocket) is Amazon's legacy e-book format for older Kindle devices. Newer Kindles support EPUB directly.
Best For:
- Older Kindle devices - Kindles from before 2024
- Backward compatibility - Legacy Kindle support
- Amazon ecosystem - If customers use older devices
Advantages:
✅ Legacy support - Works on older Kindle devices
✅ Smaller file size - Optimized compression
✅ Responsive - Text adapts to Kindle screen
✅ Amazon compatibility - Direct upload option
Disadvantages:
❌ Older technology - Outdated format
❌ Limited support - Newer Kindles use EPUB
❌ Fewer features - Less multimedia support
❌ Amazon moving away - Being phased out
❌ Limited market - Few readers still use MOBI
MOBI Specifications:
- Responsive: Adapts to Kindle screen size
- Proprietary: Amazon-specific format
- Legacy: Being phased out for EPUB
- File size: Typically small
When to Use MOBI:
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Format Recommendations by Publishing Platform
Amazon KDP (E-books)
Recommended: EPUB (native support now)
Alternative: MOBI (older devices)
NOT recommended: PDF (poor reading experience on Kindle)
Amazon KDP Print
Required: PDF
Specifications: Check size guidelines, bleed area
Resolution: 300 DPI for professional quality
Apple Books
Recommended: EPUB
Format: EPUB 3.0 or later
Specifications: Follow Apple's technical guidelines
IngramSpark
Recommended: PDF (print), EPUB (e-book)
Print: Professional PDF with bleeds
E-book: EPUB with proper metadata
Kobo & Google Play Books
Recommended: EPUB
Format: EPUB 2.0 or 3.0
Metadata: Complete book information required
Independent Bookstores & Libraries
Recommended: EPUB
Format: EPUB 3.0 preferred
DRM: Varies by distributor
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Format Selection Strategy
For Maximum Reach:
1. Create PDF for print distribution
2. Create EPUB for digital platforms
3. Include MOBI as backup (optional)
For Efficiency:
For Best Quality:
- PDF: Hire print designer
- EPUB: Hire e-book formatter
- MOBI: Auto-generate from EPUB
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Technical Specifications Summary
EPUB
MOBI
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Which Format Should You Actually Use?
If you're publishing:
Print books → Use PDF
E-books on Amazon → Use EPUB (or MOBI for legacy)
Apple Books, Kobo, etc. → Use EPUB
Maximum distribution → Create all three
One format only? → Choose EPUB
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Conclusion
The "best" book format depends on where your readers are and how they read:
- Print readers → PDF
- Tablet readers → EPUB
- E-reader users → EPUB
- Kindle users → EPUB (or MOBI for older devices)
- Ambitious authors → All three
Most successful self-published books offer PDF (print), EPUB (digital), ensuring readers can access your work on their preferred platform. Use a tool like BookFormat to generate all formats from a single source, and you'll be maximizing your reach.