What is EPUB?

EPUB is the open standard ebook format maintained by the International Digital Publishing Forum (IDPF), supporting reflowable content and DRM.

What is MOBI?

MOBI is the legacy ebook format used by Amazon for older Kindle devices, based on the Mobipocket format.

When Should You Use EPUB vs MOBI?

Use EPUB When...

Reach for EPUB when your priority is ebooks, digital publications, readers — its uncompromising quality ensures every detail is preserved.

Use MOBI When...

Reach for MOBI when your priority is older kindle devices, legacy ebooks — its efficient compression makes sharing fast and storage minimal.

EPUB vs MOBI: Key Differences

•EPUB uses lossless compression while MOBI uses lossy compression — this is the fundamental technical difference between the two formats.
•The switch from lossless compression to lossy compression means you gain significant space savings while accepting minor quality trade-offs.
•Transparency: N/A — converting from EPUB will merge transparency into a solid background
•Storage footprint: 500KB to 5MB for typical ebooks for EPUB vs 400KB to 3MB for MOBI.
•Primary audience: EPUB is built for ebooks, digital publications, readers scenarios, while MOBI focuses on older kindle devices, legacy ebooks — pick the format that matches your output requirement.

Advantages of EPUB

✓EPUB applies lossless compression specifically calibrated for Ebooks, digital publications, readers.
✓EPUB enjoys broad native support across operating systems, browsers, and creative tools alike.
✓EPUB guarantees every bit of the original data survives — no approximations, no shortcuts.
✓You will find EPUB support built into virtually every tool that handles Ebooks, digital publications, readers — no plugins or converters needed.

Advantages of MOBI

✓MOBI applies lossy compression specifically calibrated for Older Kindle devices, legacy ebooks.
✓MOBI enjoys broad native support across operating systems, browsers, and creative tools alike.
✓MOBI delivers impressive compression ratios, shrinking files dramatically while keeping visual quality high.
✓You will find MOBI support built into virtually every tool that handles Older Kindle devices, legacy ebooks — no plugins or converters needed.

Common Use Cases for EPUB to MOBI Conversion

Self-published books
Interactive content
Academic journals
Technical manuals
Accessible reading
Mobile reading

Industry Applications

Self-publishingLibrary ScienceJournalismContent MarketingAccessibilityAcademic Research

Best Practices for EPUB to MOBI Conversion

→Converting EPUB to MOBI: test the output on multiple reading devices before distribution
→MOBI offers good compatibility with various e-readers
→Include proper metadata (title, author, ISBN) for better discoverability
→Always keep a backup of your original files before converting
→Choose the appropriate quality settings for your specific use case

Troubleshooting EPUB to MOBI Conversion

!Formatting lost when converting EPUB to MOBI → complex book layouts with CSS may not transfer perfectly
!Images not displaying in the MOBI ebook → check that image formats used in EPUB are supported by MOBI
!Table of Contents broken after EPUB to MOBI conversion → some ebook formats handle navigation differently
!MOBI file has DRM issues → DRM-protected EPUB files must be unlocked (where legally permitted) before conversion

Related Ebook Converters

Convert EPUB to Other Formats

All Ebook Formats

EPUB

View all Ebook converters →

More Ebook tools

Convert to MOBI →Convert from EPUB →

Convert EPUB to MOBI Online - Free & Fast

Convert EPUB files to MOBI online for free. High-quality conversion with no registration required.

Ebook Converter

Upload or enter a URL to convert EPUB to MOBI instantly

Click to upload or drag & drop EPUB file

or paste from clipboard

.epub,.EPUB (max 100MB)

SSL EncryptedAuto-deleted in 1 hourProcessed securelyNo registration needed

Verifying security check…

About EPUB and MOBI

EPUB

EPUB is the open, industry-standard ebook format used by almost every reader except older Kindles. It reflows text beautifully and supports rich layout.

MOBI

MOBI (and its AZW descendant) is the format older Amazon Kindle devices read. Converting EPUB to MOBI lets you sideload a book onto a classic Kindle for reading on the go.

Common Use Cases

Read an EPUB on an older Kindle that lacks EPUB support.
Sideload a book via USB to a Kindle device.
Share a title with a Kindle-only reader.
Preview how a book looks in the Kindle ecosystem.

Format Comparison

CompressionLossless → Lossy

TransparencyN/A

Use CaseConvert from ebooks, digital publications, readers to older kindle devices, legacy ebooks

File Size~400KB to 3MB after conversion

FAQs

Is converting EPUB to MOBI free?

Yes, GoConvertFile offers free conversion of EPUB to MOBI for files up to 100MB.

Why convert EPUB to MOBI?

MOBI is the native format for older Kindle devices. Newer Kindles also support EPUB, but older models require MOBI for direct transfer.

How long does it take to convert EPUB to MOBI?

Most EPUB to MOBI conversions complete within seconds for standard-sized files. Larger files may take longer depending on the conversion complexity.

What is MOBI best used for?

MOBI is ideal for older kindle devices, legacy ebooks. Mobipocket, legacy Amazon Kindle format

Does converting EPUB to MOBI lose quality?

Yes, converting EPUB to MOBI uses lossy compression, which reduces file size by discarding some visual data. Set quality to 85-95% for a good balance of quality and file size.

What file size should I expect after converting EPUB to MOBI?

MOBI files are typically 50-80% smaller than EPUB files because MOBI uses efficient lossy compression. The exact reduction depends on quality settings.

Related Tools

View all ebook converter converters

What is EPUB?

EPUB is the open standard ebook format maintained by the International Digital Publishing Forum (IDPF), supporting reflowable content and DRM.

What is MOBI?

MOBI is the legacy ebook format used by Amazon for older Kindle devices, based on the Mobipocket format.

When Should You Use EPUB vs MOBI?

Use EPUB When...

Reach for EPUB when your priority is ebooks, digital publications, readers — its uncompromising quality ensures every detail is preserved.

Use MOBI When...

Reach for MOBI when your priority is older kindle devices, legacy ebooks — its efficient compression makes sharing fast and storage minimal.

EPUB vs MOBI: Key Differences

•EPUB uses lossless compression while MOBI uses lossy compression — this is the fundamental technical difference between the two formats.
•The switch from lossless compression to lossy compression means you gain significant space savings while accepting minor quality trade-offs.
•Transparency: N/A — converting from EPUB will merge transparency into a solid background
•Storage footprint: 500KB to 5MB for typical ebooks for EPUB vs 400KB to 3MB for MOBI.
•Primary audience: EPUB is built for ebooks, digital publications, readers scenarios, while MOBI focuses on older kindle devices, legacy ebooks — pick the format that matches your output requirement.

Advantages of EPUB

✓EPUB applies lossless compression specifically calibrated for Ebooks, digital publications, readers.
✓EPUB enjoys broad native support across operating systems, browsers, and creative tools alike.
✓EPUB guarantees every bit of the original data survives — no approximations, no shortcuts.
✓You will find EPUB support built into virtually every tool that handles Ebooks, digital publications, readers — no plugins or converters needed.

Advantages of MOBI

✓MOBI applies lossy compression specifically calibrated for Older Kindle devices, legacy ebooks.
✓MOBI enjoys broad native support across operating systems, browsers, and creative tools alike.
✓MOBI delivers impressive compression ratios, shrinking files dramatically while keeping visual quality high.
✓You will find MOBI support built into virtually every tool that handles Older Kindle devices, legacy ebooks — no plugins or converters needed.

Common Use Cases for EPUB to MOBI Conversion

Self-published books
Interactive content
Academic journals
Technical manuals
Accessible reading
Mobile reading

Industry Applications

Self-publishingLibrary ScienceJournalismContent MarketingAccessibilityAcademic Research

Best Practices for EPUB to MOBI Conversion

→Converting EPUB to MOBI: test the output on multiple reading devices before distribution
→MOBI offers good compatibility with various e-readers
→Include proper metadata (title, author, ISBN) for better discoverability
→Always keep a backup of your original files before converting
→Choose the appropriate quality settings for your specific use case

Troubleshooting EPUB to MOBI Conversion

!Formatting lost when converting EPUB to MOBI → complex book layouts with CSS may not transfer perfectly
!Images not displaying in the MOBI ebook → check that image formats used in EPUB are supported by MOBI
!Table of Contents broken after EPUB to MOBI conversion → some ebook formats handle navigation differently
!MOBI file has DRM issues → DRM-protected EPUB files must be unlocked (where legally permitted) before conversion

Related Ebook Converters

Convert EPUB to Other Formats

All Ebook Formats

EPUB

View all Ebook converters →

More Ebook tools

Convert to MOBI →Convert from EPUB →

Convert EPUB to MOBI Online - Free & Fast

Convert EPUB files to MOBI online for free. High-quality conversion with no registration required.

Ebook Converter

Upload or enter a URL to convert EPUB to MOBI instantly

Click to upload or drag & drop EPUB file

or paste from clipboard

.epub,.EPUB (max 100MB)

SSL EncryptedAuto-deleted in 1 hourProcessed securelyNo registration needed

Verifying security check…

About EPUB and MOBI

EPUB

EPUB is the open, industry-standard ebook format used by almost every reader except older Kindles. It reflows text beautifully and supports rich layout.

MOBI

MOBI (and its AZW descendant) is the format older Amazon Kindle devices read. Converting EPUB to MOBI lets you sideload a book onto a classic Kindle for reading on the go.

Common Use Cases

Read an EPUB on an older Kindle that lacks EPUB support.
Sideload a book via USB to a Kindle device.
Share a title with a Kindle-only reader.
Preview how a book looks in the Kindle ecosystem.

Format Comparison

CompressionLossless → Lossy

TransparencyN/A

Use CaseConvert from ebooks, digital publications, readers to older kindle devices, legacy ebooks

File Size~400KB to 3MB after conversion

FAQs

Is converting EPUB to MOBI free?

Yes, GoConvertFile offers free conversion of EPUB to MOBI for files up to 100MB.

Why convert EPUB to MOBI?

MOBI is the native format for older Kindle devices. Newer Kindles also support EPUB, but older models require MOBI for direct transfer.

How long does it take to convert EPUB to MOBI?

Most EPUB to MOBI conversions complete within seconds for standard-sized files. Larger files may take longer depending on the conversion complexity.

What is MOBI best used for?

MOBI is ideal for older kindle devices, legacy ebooks. Mobipocket, legacy Amazon Kindle format

Does converting EPUB to MOBI lose quality?

Yes, converting EPUB to MOBI uses lossy compression, which reduces file size by discarding some visual data. Set quality to 85-95% for a good balance of quality and file size.

What file size should I expect after converting EPUB to MOBI?

MOBI files are typically 50-80% smaller than EPUB files because MOBI uses efficient lossy compression. The exact reduction depends on quality settings.

Related Tools

View all ebook converter converters