EPUB Reader Online

What Is an EPUB File?

EPUB is the open standard format for ebooks. Most bookstores, public library apps and free ebook sites publish their books as EPUB, and almost every reading app except Amazon's Kindle supports it. The current version of the format is maintained by the W3C, and the full technical description is available in the EPUB 3.3 specification.

Under the hood, an EPUB is a ZIP archive with a fixed structure. Each chapter is a small XHTML web page, styled with CSS, with images and fonts stored alongside it. A package file lists every item in the book and the order in which the chapters should be read, and a navigation document provides the table of contents. Because the content is essentially HTML, the text reflows to fit the screen: make the font bigger and the book simply gains more pages, which is why EPUB works so well on phones.

That design is also why a web browser is a natural place to read one. Browsers already know how to display HTML and CSS. An online EPUB reader such as the one above unpacks the archive in your browser tab, follows the reading order, and displays each chapter in a sandboxed frame with the page-turning, contents and settings you would expect from a reading app.

How to Open an EPUB File on Any Device

The steps are the same everywhere: open this page, choose the file, and start reading. What differs is where your EPUB files are stored and what built-in options each platform offers.

Windows

Windows has no built-in EPUB reader. Microsoft Edge used to open EPUB files, but that feature was removed, so double-clicking a book now usually asks you to pick an app. The browser reader avoids that: drag the file from File Explorer onto the reader and it opens at once. If you prefer a desktop app with a library, compare the options in our guide to the best EPUB readers for Windows.

Mac

Apple Books opens EPUB files on macOS, but it imports each book into its own library and syncs it to iCloud. When you just want to look at a file, check how it renders, or read on a shared computer, opening it in the browser is quicker. See our roundup of the best EPUB readers for Mac for app alternatives.

iPhone and iPad

In Safari, tap Choose EPUB File and select the book from the Files app, iCloud Drive or another storage provider. Swipe left and right to turn pages, and use the Aa menu to increase the text size. Apple Books is the default app for EPUBs on iOS, and there are others worth trying in our list of the best EPUB readers for iPhone and iPad.

Android

Android does not include a dedicated EPUB reader. In Chrome, open this page, tap the button and pick the book from Downloads, Google Drive or your file manager. For a reader that lives on your home screen, browse the best EPUB reader apps for Android. If your collection includes Kindle files, the guide to the best MOBI readers for Android covers those too.

Chromebook

ChromeOS has no native EPUB app, which makes a browser reader the simplest choice. Open the book from the Files app or drag it from the Downloads folder onto the reader. Because everything runs in the browser, it works the same on school and managed Chromebooks where installing extensions or Android apps is blocked. More options are in our Chromebook EPUB reader guide.

Linux

Firefox and Chromium on Linux run the reader without any extra packages. For a desktop app with library management, see the best EPUB readers for Ubuntu.

Browser EPUB Reader vs an Installed App

A browser reader and a dedicated app solve slightly different problems. Neither is better in every case, so it helps to know where each one fits.

• Nothing to install. A browser reader works on locked-down work and school computers, borrowed devices and Chromebooks.
• Private. This reader never uploads the book. Some online viewers do send your file to a server, so check before using one with personal or unpublished documents.
• Same experience everywhere. The reader looks and behaves the same in every modern browser and operating system.
• Apps are better for large libraries. Installed readers keep a library, sync progress between devices, and support highlights, notes and dictionaries.
• Apps handle store purchases. Books from the Kindle, Kobo or Google Play stores are usually locked to their own apps.

A good rule of thumb: use the browser reader for opening a file quickly, previewing a book you are writing or editing, and reading DRM-free books on any device; install an app when you want a permanent library. The EPUB tools and guides hub links to every reader comparison on this site.

Where to Find Free, DRM-Free EPUB Books

Project Gutenberg offers tens of thousands of public domain books as free EPUB downloads, from classic novels to history and science. Standard Ebooks takes public domain texts and produces carefully proofread editions with good typography and cover art. Both are DRM-free and open perfectly in this reader. Many independent authors and technical publishers also sell DRM-free EPUBs.

Tips for Comfortable Reading in the Browser

1. Use full screen mode to hide the browser and page around the book, then turn pages with the arrow keys or Page Up and Page Down.
2. Switch to the sepia or dark theme in the evening. Both change the page and the reader frame, not just the text.
3. If lines feel cramped, raise the line spacing before increasing the font size. Wider margins also shorten the line length, which many readers find easier.
4. Try the dyslexia-friendly font option. It uses a font such as OpenDyslexic or Atkinson Hyperlegible when one is installed, and otherwise a clear sans-serif with extra letter and word spacing.
5. Turn on the two-page spread on a wide monitor for a printed-book feel, or choose scrolled mode if you prefer to read like a web page.
6. Use search to find a character's first appearance or a quote you remember, then press the result to jump straight to it.

If you are preparing your own ebook, the reader is a quick way to check how the chapters, images and table of contents look before publishing. To correct a word or name throughout the book, use EPUB Find and Replace, and if a book is split across several files you can merge EPUB files into one.

Troubleshooting: When an EPUB Will Not Open

The reader says the book is protected with DRM

Store-bought books are often encrypted with DRM such as Adobe ADEPT, Apple FairPlay or Readium LCP. The chapters cannot be decrypted outside the store's own apps, so no browser reader can show them. Open the book in the app you bought it from, or look for a DRM-free edition. Kindle purchases are always locked to Kindle apps and devices.

The file is a MOBI, AZW or PDF

These are different formats. MOBI and AZW are Kindle formats; if they are DRM-free you can convert them to EPUB with Calibre, or open them with one of the MOBI readers for Windows. PDFs should be opened in a PDF viewer.

The book opens but some pages look wrong

Fixed-layout EPUBs, such as comics and children's picture books, are designed page by page and may not reflow neatly. Choose Publisher font, reset the settings, and try paginated mode without the spread. Interactive books that rely on scripts will also look static, because scripts inside the book are disabled here for your safety.

The file is reported as damaged

An interrupted download often leaves a truncated ZIP archive. Download the book again and retry. If you want to inspect what is inside an EPUB, rename a copy to .zip and open it, or view its chapter files with the Large Text File Viewer.

Your reading position was not remembered

Positions are saved in your browser's local storage, keyed to the book. They are not available in a private window, after clearing site data, or on another device or browser. Opening the same book file again in the same browser will offer to continue where you left off.