Which eBook Format Should I Choose?
As distribution channels evolve, the decision about which format is best becomes simpler.
A decade ago, when ePub was emerging, ebook distribution channels like Amazon and Kobo developed their own ePub standards, which resulted in a confusing array of formats required from publishers.
Today, by contrast, there are only two formats required to reach those channels: ePub3 and PDF.
Here's a breakdown of popular ebook formats and the platforms they serve:
1. ePub This is a widely accepted ebook format that's supported by many reading devices and apps. It's the standard format for the International Digital Publishing Forum (IDPF). Apple Books uses ePub, and many other platforms support it. It's a flexible format that can be made to be reflowable or fixed-layout, depending on the type of content. As of May 2023, the standard is ePub3.3, described here.
2. MOBI/KF8/AZW3 These are formats once used by Amazon for its Kindle devices and apps. MOBI is the older format, while KF8 (Kindle Format 8) and AZW3 are newer and support more advanced features. If you're distributing only through Amazon, they'll often convert ePub files to their proprietary formats. When you use Amazon's Kindle Direct Publishing (KDP) platform, you can upload an EPUB file, and they will automatically convert it.
3. PDF While technically an ebook format, PDFs are not reflowable like ePub or MOBI, which means they maintain a fixed layout regardless of the device or screen size. They're great for content where layout is essential (like graphic novels or magazines), but they might not offer the best reading experience on smaller devices.
Given the above formats, here's a strategy for publishers:
For Maximum Flexibility and Compatibility, start with an ePub file. It's versatile, widely accepted, and can be converted to other formats relatively easily.
For Amazon If you're publishing on Amazon, they will take your ePub and convert it. However, if you want more control over the final appearance on Kindle devices, you might consider converting the ePub to KF8/AZW3 yourself using Amazon's tools like Kindle Previewer and KindleGen.
For Apple Apple Books primarily uses ePub, so you're good to go with that format.
For Direct Sales or Specialized Content If you're selling directly from your website or have content where the design and layout are important, providing an additional PDF version might be beneficial. But bear in mind the advice from DAISY referenced below.
In Summary
In Summary
ePub3 is the most versatile and widely accepted format for ebook distribution. Start with a high-quality ePub file, and then consider additional formats based on specific platform requirements or needs.
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