Everything you need to know about the EPUB format and how to open it on any device.
EPUB (short for Electronic Publication) is the most widely used ebook file format in the world. It is an open standard designed specifically for digital books, developed and maintained by the International Digital Publishing Forum.
The key characteristic of an EPUB file is that it is reflowable. This means the text automatically adapts to the size of the screen you are reading on. Whether you open an EPUB on a small phone or a large tablet, the text resizes and reflows to fit perfectly, making it far more comfortable to read than a fixed-layout format like PDF.
An EPUB file is technically a compressed archive that contains the text of the book in HTML, along with images, styling information, fonts and metadata such as the title, author and table of contents.
EPUB has become the industry standard for ebooks for several reasons:
The only major platform that does not support EPUB natively is Amazon Kindle, which uses its own formats called MOBI and AZW3.
Opening an EPUB file is easy once you have the right app for your device. Here is how to do it on each platform:
Use free apps like Calibre, Adobe Digital Editions, or the EPUB reader available in the Microsoft Store. Microsoft Edge can also open EPUB files directly in some versions.
Apple Books comes pre-installed on every Mac and opens EPUB files natively. Just double-click the file and it will open automatically.
Apple Books is built into iOS. Open the EPUB file from an email or download and choose "Copy to Books" to read it instantly.
Use Google Play Books, Moon+ Reader, or ReadEra. Most are free and open EPUB files directly from your device storage.
Kobo eReaders support EPUB natively. Simply transfer the file via USB or use the Kobo desktop app to sync it to your device.
Kindle does not support EPUB directly. You need to convert your EPUB to MOBI or AZW3 first, then transfer it to your device.
Since Amazon Kindle does not support EPUB natively, you need to convert your file to a Kindle-compatible format first. This is quick and free with EPUBKit.
Convert your EPUB to AZW3 for modern Kindle devices, or to MOBI for older models. Once converted, you can transfer the file to your Kindle via USB or send it wirelessly to your Kindle email address.
Tip: With EPUBKit you can convert your EPUB and send it directly to your Kindle in one step, using the Send to Kindle button available after every conversion.
The main difference is that EPUB is reflowable and PDF is fixed-layout. An EPUB adapts its text to your screen, while a PDF always looks exactly the same regardless of the device.
EPUB is better for reading books on phones, tablets and eReaders because the text is comfortable to read at any size. PDF is better when you need to preserve an exact layout, such as for printing, forms or documents with complex formatting.
If you have a PDF that is uncomfortable to read on your phone, converting it to EPUB can dramatically improve the experience.
Some web browsers like Microsoft Edge can open EPUB files directly. However, for the best reading experience a dedicated ebook app such as Apple Books, Calibre or Google Play Books is recommended.
Yes. EPUB files themselves are safe as long as you download them from a trusted source. They contain text, images and styling, not executable code.
Yes. EPUBKit lets you convert EPUB to PDF, MOBI and AZW3 for free. You can also convert PDF files back to EPUB.
Kindle does not support EPUB natively. You need to convert your EPUB to MOBI or AZW3 first. Both conversions are free on EPUBKit.