You have probably already heard or encountered digital book formats with different extensions. EPUB and MOBI are the most popular e-book formats, but Windows does not open them out of the box. In this article, we explain how to open EPUB, how to open MOBI, and how to edit or convert files for free. All this can be done both on a laptop and on a desktop personal computer.
Briefly about formats
- EPUB is an open container, supported by most readers, scales to fit the screen size.
- MOBI is the “native” format of Amazon Kindle; for PC you need third-party software.
Now we need to solve a fairly simple problem, namely reading and editing such files.
How to open EPUB on Windows 10 / 11
- Calibre (recommended) – free library + reader. Opens EPUB, FB2, PDF and dozens of other formats.
- Sumatra PDF — super lightweight (≈5 MB), there is a portable version.
- FBReader — minimalist reader with bookmark synchronization.
- EPUB Reader extension for Edge or Chrome — “nothing to install”.
How to open MOBI on a computer
- Kindle for PC — official Amazon program, perfectly renders MOBI and DRM books.
- Calibre — universal: reads both MOBI and EPUB, converts between them.
- Sumatra PDF — displays MOBI without installation fonts Kindle.
Universal programs “two in one”
Here is a small comparative table.
| Program | Reading | Editing | Conversion | Pros | Cons |
|---|---|---|---|---|---|
| Calibre | ✔ EPUB, MOBI | Limited (plugins) | ✔ EPUB⇆MOBI | All-in-one, catalog, metadata | Busy interface |
| Sigil | EPUB | ✔ fully functional | EPUB→MOBI via plugin | WYSIWYG + code | EPUB only |
| Kindle Previewer | MOBI | Preview | MOBI→KPF | Accurate display of Kindle | No EPUB |
How to edit EPUB and MOBI
- EPUB → Sigil
Open the file, correct styles or table of contents, save – the structure will not break. - MOBI → Calibre
Convert MOBI to EPUB, edit in Sigil or Calibre (metadata, cover) and return to MOBI if necessary.
Convert EPUB ⇆ MOBI
# Calibre CLI (ebook-convert)
ebook-convert book.epub book.mobi --enable-heuristics
In graphic mode: «Convert books» → select format.
FAQ
Does Calibre slow down my PC?
Calibre uses ≈200 MB of RAM on a large library; to read one book, you can use Sumatra PDF.
How to open EPUB on Windows 7?
Portable Sumatra PDF or Calibre 5.x works on Windows 7 SP1.
Can I read MOBI on my smartphone?
Yes, with the Kindle app (Android / iOS) or FBReader with a plugin.
Now you know how to open an EPUB file and how to open MOBI on a PC, as well as how to easily edit and convert them. Share your life hacks in the comments!
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