Most Popular eBooks Formats of 2021

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Sales of digital books hit an all-time high this year. On the one hand, the ebook market has received a boost thanks to the government scrapping the reading tax of 20% VAT charged on digital titles. On the other hand, consumers stuck at home due to the COVID-19 pandemic are spending more money on books than ever before. Though the ebook market has been growing year by year, do you even know what are the most popular ebook formats out there? And how to choose the right ebook formats? In this article, we're going to talk about the most popular ebook formats, the differences between them, and some useful tips that you need to know.

most popular ebook formats

1. Most popular ebook formats of 2021

According to official statistics, there are the top 6 most popular ebook formats of all time - PDF, EPUB, MOBI, TXT, AZW3, and DOC/DOCX. Let's take a detailed look at these popular ebook formats and choose the right one which works the best for you.

best popular ebook formats


PDF files, also known as Portable Digital Files, were invented by Adobe in the 90s. They used to be the preferred ebook format. The word portable means that it's supposed to look and behave the same no matter where and how the file is. The main characteristic of PDFs is that they preserve the layout, formatting, fonts, and images within the document. Of course, PDF is not primarily used for editing. Content can't be changed easily. Since PDF was created as an open standard format from the beginning, it has attracted a large and diverse group of third-party developers who have helped to make it wildly popular. Finally, one of the most important reasons that PDF is so popular is that the PDF viewer, like Adobe Reader, is free. Chances are you'll be able to open a PDF directly from your internet browser. Anyone can view and use PDF files at no cost.


 – Portable: PDF file preserves the formatting and looks the same on all devices.;

 – Easy for viewing: PDFs can be opened straight from any modern browser or mobile device.


 – Difficult to edit the text in PDF files, plus a specialized program is required to change the content in PDF files.


EPUB, short for Electronic Publication, is an open standard ebook format. The EPUB standard was established by the International Digital Publishing Forum, which updates the format regularly. The current standard is EPUB 3. EPUB now also supports fixed-layout content, but EPUB is designed for reflowable content that can adapt its presentation to the reader device.

The EPUB format is the most widely supported e-book format, supported by most e-book readers except Amazon Kindle. And for this reason, it is preferred by most digital retailers and publishers, like Apple, Kobo, Nook, Google Play books, etc.


– Flexible, reflowable, highly interactive: allows text to fit any size screen, and allows users to change fonts, font size, colors, backgrounds...

- Compatibility: supported by the majority of ereaders and reading apps.


- Strict requirements for creating a zip archive for EPUB.


Another most commonly used file format is MOBI created by Mobipocket. As the name suggests, it is mainly used in smartphones that have low bandwidth because the MOBI file has included multiple components like bookmarking, frames, , highlighting, and adding annotations, etc.

MOBI became the proprietary ebook format of Amazon after Mobipocket was acquired by Amazon in 2005. The most distinguishing feature of MOBI is that can be opened by all Kindle apps and devices. It was also the first as well as the most widely used ebook file format used by Amazon when it launched Kindle. And .mobi files must consist of DRM copyright protection feature which helps to prevent unauthorized users from copying.


- Maintaining the original format: retains the presentation of the content as in an original manner at any output device;

- Supports high degree compression and indexing;

- Advanced navigation controls.


- MOBI files sometimes have trouble converting tables and images on different size devices;

- Technical glitches can prevent the cover from loading properly.


Do you know that the first e-books in history were in plain text (.txt) format? TXT, which stands for textfile, is a text document that contains only plain text. All the text contained in such a file is in human-readable format and represented by a sequence of characters. Although txt files have little or no formatting, it is the best file format for storing a large amount of data persistently as there is no limitation on the size of contents. And almost all operating systems come with text editors that allow you to view and edit text files.


- Universal: TXT files can be edited and opened in any text editor or word processing application on almost all operating systems;

- Great for text-heavy eBooks.


- Have little or no formatting at all;

- Images and graphs are not supported.


Another popular Kindle ebook file format - AZW3, also called Kindle Format 8 (KF8), is the successor to the AZW ebook file format developed for Amazon Kindle devices. Unlike AZW files, AZW3 files support markup languages like HTML5 and CSS3. Besides, it has more formatting options than the old AZW files. AZW3 files are binary in nature and retain the structure of a MOBI file format as PDB file. So the AZW3 file may consist of both a MOBI as well as an EPUB. Basically, AZW3 is a compiled EPUB that has been compiled using a Palm database and Amazon's DRM scheme. Compared to MOBI, AZW3 has better performance. And it is much smaller in size.


- Can download directly from Amazon Store;

- Allows many of the more complex formatting options.


- Not widely supported on reading apps and devices as EPUB and PDF do.


DOC and DOCX are well-known formats for Microsoft Word documents. They are proprietary to Microsoft Word for their saved files. DOC and DOCX files can contain many types of data such as images, formatted as well as plain text, graphs, charts, embedded objects, links, page formatting, print settings and a lot of others. DOCX is an advanced version of the DOC file format and is much more accessible than DOC. Both DOC and DOCX are popular due to the content can be reflowed and easily edited.


- Allow easy editing and reflowing of documents.


- Supported by few ebook readers.

Frequently Asked Questions
Q: Which ebook format should I choose?

You can choose the right ebook formats depending on your device compatibility and reading needs. If you want to read ebooks on Kindle devices, then you should narrow down your choice to Kindle support file formats. If you want to print your ebooks out, then PDF is the best option for you. Or if you want to edit the content easily, you should try TXT or DOC/DOCX file format.

Q: What e-reading software do I need to read an ebook?

Due to compatibility problems, different formats require different e-reading devices or reading apps to open them. So you can choose the correct reading software based on your ebook file formats. If you want to view Mobi files, we'd recommend you use the Kindle app or freeware calibre.

Q: What are the major ebook stores?

Amazon, Barnes & Noble, Google Play, Kobo and Apple books are the big dogs on the ebook scene.

Q: What is DRM used for?

DRM stands for Digital Rights Management. The purpose of DRM is to restrict the use and distribution of copyrighted works by locking them to a specific platform. For example, DRM encrypted Kindle books can only be read with Kindle apps and Kindle devices. Even worse, you have only been granted the right to access your purchased contents without being able to share them with your loved ones.

Q: Which ebooks formats support DRM?

Popular Ebook formats, like EPUB, AZW, AZW3, PDF, support DRM perfectly. Usually, your purchased ebooks downloaded from the major ebook stores come with DRM protection. Well, ebook formats like TXT and DOC/DOCX can’t support the DRM protection scheme.

Q: How to convert ebook format?

Ebook converter tool can be used to convert ebooks from one format to another. Converting your DRM free ebooks to common ebook formats with the free online ebook converters is a good choice. However, if your ebooks are DRM encrypted, a simple yet powerful DRM Removal is required to remove DRM first. Then convert the decrypted files to other formats according to your needs.

Bonus TipsHow to remove DRM from my purchased ebooks?

Epubor Ultimate is the top-notch DRM Removal in the market, which can help you get rid of DRM from Amazon/Kobo/Google Play/Nook books with minimal effort. Besides, it can convert your ebooks to PDF/MOBI/AZW3/TXT/EPUB. It is definitely worth a shot.

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works for Epubor and writes articles about eBooks and eReaders. She explores the best method to help you read eBooks more freely and wants to share all she has got with you.

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