Kindle eBook Formats: Publishing vs Personal Files

Updated 6 November 2026 · Standard formula, shown below

For publishing on Amazon, use Kindle Create (KPF) or a well-formed EPUB converted through Kindle Direct Publishing; for personal files, use MOBI or AZW3 for older Kindles and EPUB for newer ones. This article explains the differences, how to choose, and how to convert files for both purposes.

Background: How Kindle Formats Evolved

Amazon introduced the Kindle in 2007 with a proprietary format called AZW, which was essentially a MOBI file with a different extension and DRM. Over the years, Amazon added AZW3 (also called KF8) to support richer formatting like drop caps and nested tables. In 2022, Amazon announced it would phase out MOBI and AZW3 for newer devices, shifting to EPUB as the standard for sending documents to Kindles via Send to Kindle. For publishers, Amazon now accepts EPUB and DOCX, and recommends using Kindle Create to produce a KPF file that converts to the latest Kindle formats automatically.

How It Works: What Each Format Actually Does

Kindle devices and apps read several file types, but not all are equal in features. Here’s a breakdown:

MOBI – Older format, supports basic text and images, no advanced layout. Still readable on most Kindles, but Amazon no longer supports it for new transfers.
AZW3 (KF8) – Adds support for CSS styling, drop caps, and better table handling. Works on Kindle Fire and newer e-ink devices, but not on the oldest models.
EPUB – The industry standard, now accepted by Amazon for Send to Kindle. It preserves complex layouts and is the source for most converted files.
KPF (Kindle Package Format) – Created by Kindle Create, this is a project file that Amazon converts to the appropriate format for each device.
PDF – Not a true reflowable format; it’s a fixed page image. Works for documents with complex layouts but poor on small screens.

When you send a file to your Kindle via email or the Send to Kindle app, Amazon automatically converts EPUB, MOBI, AZW3, DOCX, and PDF to a format your device can read. For MOBI, Amazon stopped supporting it in 2022, so it may not be delivered to newer devices.

How to Choose: Publishing vs Personal Files

Your choice depends on your goal. For publishing on Amazon KDP, the official recommendation is to use Kindle Create or upload a DOCX/EPUB file. For personal use, the best format depends on your device and how you transfer files.

Publishing: Use Kindle Create (free) to make a KPF, or upload a properly formatted EPUB. Avoid MOBI entirely—Amazon no longer accepts it for new titles.
Personal files (newer Kindles, 2022+): Use EPUB via Send to Kindle. It’s the most future-proof and preserves formatting.
Personal files (older Kindles, pre-2022): Use MOBI or AZW3. These devices may not support EPUB natively, but you can convert EPUB to AZW3 with Calibre.
Personal files (Kindle Fire/Tablet): Use the Kindle app, which reads EPUB, MOBI, and AZW3, or use the Kindle app’s “Send to Kindle� feature.

Common Problems and Misconceptions

One common mistake is assuming all Kindles read the same formats. Older e-ink models (like Kindle Keyboard, Kindle 4, and Kindle 5) cannot read EPUB without conversion. Another misconception is that MOBI is still supported for Send to Kindle—it’s not, as of 2022. If you send a MOBI file to a newer Kindle, you may get an error or the file may not appear. Also, PDFs don’t reflow, so reading a PDF on a small screen can be frustrating. For personal documents, convert to EPUB or AZW3 for a better reading experience.

How to Convert Files: Tools and Steps

If you have a file in the wrong format, you can convert it using free tools. The most popular is Calibre, a desktop program that supports almost every ebook format. Here’s a simple workflow:

Download and install Calibre on your computer.
Add your ebook file (e.g., EPUB, MOBI, PDF) to Calibre’s library.
Select the book and click “Convert books� in the toolbar.
Choose the output format (e.g., AZW3 for older Kindles, EPUB for newer).
Click OK, and Calibre will create the converted file.
Transfer the file to your Kindle via USB, or use Calibre’s “Send to device� feature.

For publishing, Amazon’s Kindle Create tool is the recommended route. It’s free and ensures your book displays correctly on all Kindle devices. You can also upload a well-formed EPUB directly to KDP, but you should preview it in the KDP previewer to check for issues.

Costs and Safety

Converting files for personal use is free—Calibre is open-source. Kindle Create is also free. For publishing, Amazon charges no upfront fee, but takes a royalty percentage (35% or 70% depending on list price and delivery fees). There are no safety concerns with file formats themselves, but be cautious when downloading ebooks from unofficial sources—they may contain malware. Always use trusted sources like Amazon, your local library, or Project Gutenberg.

Alternatives to Native Kindle Formats

If you don’t want to deal with Kindle-specific formats, you can use the Kindle app on your phone or tablet, which supports EPUB and PDF. You can also use Amazon’s “Send to Kindle� web page to upload files directly. Another option is to use a third-party reader app like Moon+ Reader or FBReader, which support EPUB, MOBI, and other formats, but they won’t sync with your Kindle.

Frequently Asked Questions

Can I still send MOBI files to my Kindle?

As of 2022, Amazon no longer supports MOBI for Send to Kindle. If you try to send a MOBI file, you’ll get an error. However, you can still transfer MOBI files via USB, and older devices will read them.

What is the best format for a Kindle Paperwhite?

For a Paperwhite (10th generation and newer), EPUB is the best format for personal files because it’s the current standard and preserves formatting. For older Paperwhites (2018 and earlier), use AZW3 or MOBI.

Does Kindle support PDF?

Yes, Kindles can display PDFs, but they don’t reflow text, so you’ll have to zoom and pan. For novels or text-heavy documents, convert to EPUB or AZW3 for a better experience.

What is the difference between AZW3 and KPF?

AZW3 is a file format that your Kindle reads. KPF is a project file used by Kindle Create—it’s not a final ebook file. When you publish, Amazon converts KPF to the appropriate format for each device.

Can I read EPUB on a Kindle without converting?

Yes, if you have a Kindle with software version 5.15.1 or later (released in 2022), you can send EPUB files directly via Send to Kindle. Older devices will need conversion.

What format should I use for a Kindle Fire?

Kindle Fire tablets use the Kindle app, which supports EPUB, MOBI, AZW3, and PDF. You can also use the Send to Kindle app to transfer files wirelessly.

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