What is the best free EPUB reader?

Calibre is the most capable and runs on Windows, macOS and Linux, handling reading, library management and conversion. SumatraPDF is much lighter on Windows if you only want to read. Apple Books is already installed on macOS.

Can I convert EPUB to PDF?

Yes, Calibre converts between EPUB, PDF, MOBI and AZW3. Be aware that EPUB reflows and PDF does not, so converting fixes the text to a page size and usually reads worse on a phone.

Why will my purchased EPUB not open in Calibre?

It carries DRM tying it to the retailer. Calibre will not open protected files. Read it in the store's own application, on the account that bought it.

File extensions

How to open a .epub file

Electronic publication · Ebook

An .epub file is an ebook. Calibre opens it on any desktop, and SumatraPDF is a lighter option on Windows. If it refuses to open, the book is DRM-protected and tied to the store you bought it from.

What a .epub file actually is

EPUB is the open ebook standard from the W3C. Internally it is a ZIP containing XHTML, CSS and images, which is why the text reflows to fit any screen instead of being fixed to a page like a PDF.

That openness is only half the story in practice. Most commercially sold EPUBs are wrapped in DRM, and a DRM-wrapped file behaves like a completely different format as far as your reader is concerned.

Why it will not open

Neither Windows nor macOS ships an EPUB reader on the desktop, so nothing is associated with the file. Separately, a book bought from a store may carry Adobe or store-specific DRM, in which case only an authorised app will open it no matter what you install.

Step by step

Windows

01Install Calibre, the standard desktop ebook manager, or SumatraPDF if you only want to read.
02Double-click the .epub, or drag it into Calibre and use "View".
03You can also drag the file into Microsoft Edge, which has a built-in reader for unprotected EPUBs.
04If you are told the file is invalid or protected, it has DRM. Open it in the reader app of the store you bought it from.

macOS

01Double-click. Apple Books opens EPUB natively.
02Install Calibre if you want to manage a library, convert formats or send books to an e-reader.

What usually goes wrong

DRM is not a corruption problem

A protected EPUB often reports itself as damaged or unsupported, which sends people looking for repair tools. Nothing is wrong with the file. It is encrypted to an account, and the only supported way to read it is the store's own app.

Programs that open .epub

Our pick, in order. Every one links to the publisher's official download URL and the SHA-256 hash of the installer, so you can check the file before you run it.

Also registers .epub in its manifest

Taken straight from publisher manifests. Some of these handle the format for a narrow purpose rather than as their main job.

Yandex Browserv26.6.3.870 · 1 hashed installer100

Common questions

What is the best free EPUB reader?: Calibre is the most capable and runs on Windows, macOS and Linux, handling reading, library management and conversion. SumatraPDF is much lighter on Windows if you only want to read. Apple Books is already installed on macOS.
Can I convert EPUB to PDF?: Yes, Calibre converts between EPUB, PDF, MOBI and AZW3. Be aware that EPUB reflows and PDF does not, so converting fixes the text to a page size and usually reads worse on a phone.
Why will my purchased EPUB not open in Calibre?: It carries DRM tying it to the retailer. Calibre will not open protected files. Read it in the store's own application, on the account that bought it.