EPUB Reader
Open an .epub e-book and start reading right away: turn pages with buttons, arrow keys or swipes, jump through the table of contents and set the font size and style you like.
Opening book…
How to use the EPUB Reader
- Open an EPUB by dropping it into the box or clicking to choose a file.
- Turn pages with the ‹ and › buttons, the left and right arrow keys, or by swiping on a phone.
- Jump to a chapter with the Contents menu.
- Adjust the text: A− and A+ change the size, and you can pick the font, spacing and theme.
- Come back later: the reader remembers where you stopped in each book.
What is inside an EPUB file
An EPUB is a ZIP archive with a fixed structure. The reader opens it in this order:
| File | Purpose |
|---|---|
mimetype | The text application/epub+zip, stored first and uncompressed |
META-INF/container.xml | Points to the package file (OPF) |
content.opf | Title, author and language, the manifest of every file, and the spine (reading order) |
nav.xhtml (EPUB 3) or toc.ncx (EPUB 2) | The table of contents shown in the Contents menu |
*.xhtml | The chapters, written in XHTML |
*.css, images, fonts | Styling, illustrations and embedded typefaces |
How pages are calculated
E-books are reflowable, so there is no fixed page count. The reader lays each chapter out in CSS columns exactly as wide as the reading area and shows one column at a time:
pages in chapter = total laid-out width ÷ width of the reading area
A larger font, wider spacing or a narrower window means fewer words per page and more pages. For a rough idea, at 18 px and normal spacing a desktop page holds about 250–350 words, and a phone page about 120–180 words. A typical 80,000-word novel is therefore roughly 250–320 pages on a desktop.
Where to find free, legal EPUB books
- Project Gutenberg: over 70,000 public-domain classics, all DRM-free.
- Standard Ebooks: carefully formatted public-domain books with clean typography.
- Your local library: many libraries lend DRM-free titles, or titles you can read in their own apps.
- Authors and publishers: many sell DRM-free EPUBs directly; look for "DRM-free" on the store page.
Keyboard shortcuts: → or Page Down for the next page, ← or Page Up for the previous page. On touch screens, swipe left or right, or tap the right or left edge of the page.
Frequently asked questions
Is my book uploaded anywhere?
No. The EPUB file is unzipped and displayed entirely in your browser with JSZip. The book never leaves your device, and your reading position is stored only in this browser.
Can it open DRM-protected books?
No. Books bought with DRM (for example from some e-book stores) are encrypted and can only be opened by their store's app. DRM-free EPUBs, such as public-domain books from Project Gutenberg or Standard Ebooks, open fine.
What is an EPUB file?
EPUB is the standard open e-book format. An .epub file is a ZIP archive containing the chapters as XHTML pages, stylesheets, images and a package file that lists the reading order and table of contents.
Why do pages change when I resize the window or the font?
EPUB books are reflowable: the text is re-laid out to fit the screen and your font settings, so the number of pages changes. The reader keeps you at the same place in the chapter.
Are scripts in the book run?
No. For safety, scripts, event handlers, forms and embedded frames are removed and the chapter is shown in a sandboxed frame. Ordinary text, images, links and styling work as intended.
Can I read Kindle (MOBI or AZW) files?
This reader supports EPUB only. Kindle formats can be converted to EPUB with free desktop software such as Calibre, as long as they are not DRM protected.