BookShelves opens ebooks and comic books in the formats below. Some open as they are; others are converted once, while they are imported: ebooks to EPUB, CBR and CB7 comics to CBZ. Either way the book lands in your library ready to read.
For the ways to get files into the app, see Importing Books.
Ebook formats
| Format | Extensions | How it works |
|---|---|---|
| EPUB | .epub | Opened as is. The most widely used ebook format. |
| KEPUB | .kepub.epub, .kepub | Kobo’s variant of EPUB. .kepub.epub files open as EPUB; .kepub files are converted to EPUB on import. |
.pdf | Opened as is. Two-page spreads on larger screens. | |
| MOBI | .mobi, .prc | Converted to EPUB on import. The older Kindle format. |
| AZW / AZW3 / KF8 | .azw, .azw3, .kf8 | Converted to EPUB on import. Newer Kindle formats. |
| FB2 | .fb2, .fb2.zip | Converted to EPUB on import. Common for Russian and Eastern European books. |
| Plain text | .txt | Converted to EPUB on import. |
| Markdown | .md | Converted to EPUB on import. |
What conversion means
Conversion happens once, during import. After that the book behaves like any other EPUB or CBZ: same reader, same settings, same sync. Your original file is not changed.
Comic book formats
| Format | Extensions | How it works |
|---|---|---|
| CBZ | .cbz | Opened as is. A ZIP archive of page images. |
| CBR | .cbr | Converted to CBZ on import. A RAR archive of page images. |
| CB7 | .cb7 | Converted to CBZ on import. A 7z archive of page images. |
Comics open in the comic reader, which has single-page and two-page layouts and right-to-left page order for manga. See Reading Comics.
What BookShelves cannot open
DRM-protected files. Books locked with copy protection (DRM), which covers many store purchases and library loans, cannot be opened. BookShelves tells you and skips the file. This depends on the protection, not the format: a DRM-free MOBI imports fine, a DRM-locked EPUB does not.
DJVU, LIT, DOC and DOCX. These are not supported. Converting them to EPUB or PDF with Calibre first is the simplest route.
When a book comes in several formats
When you import a Calibre library that holds the same book in more than one format, BookShelves imports one copy and picks the format in this order:
CBZ > CBR > CB7 > EPUB > FB2 > MOBI / PRC / AZW / AZW3 / KF8 > KEPUB > TXT > Markdown > PDF
Comic archives come first, so a comic stored as both CBZ and PDF opens in the comic reader. PDF comes last because reflowable formats adapt to your screen and reader settings.
Still have questions?
If a file won’t open or you’re not sure a format is supported, ask on the feedback portal and include the file extension.