Home·File extensions

.fb2

E-books · application/x-fictionbook+xml

Opens with

CalibreFBReader

E-book formats. Unlike paper, the text reflows to fit whatever screen you read it on.

MIME typeapplication/x-fictionbook+xml
CategoryE-books
Opens in a browserNo
Plain textYes
Registered typeUnofficial (x-)

How to read this

  • An extension is a label, not the contents. Rename a file to .png and if the bytes inside are JPEG, it is still a JPEG.
  • A MIME type is how the internet names a file kind. Browsers look at that value, not the extension, to decide whether to display or download.
  • A MIME type starting with x- was never registered as a standard. Plenty are in wide use, but they are not official names.
  • Video extensions name a container. The same .mp4 may play on one device and not another, depending on the codec inside.

Frequently asked questions

Q. What is a .fb2 file?

It belongs to the e-books category and its MIME type is application/x-fictionbook+xml. The contents are plain text, so you can even open it in Notepad and read it.

Q. What opens a .fb2 file?

Calibre, FBReader all handle it. In a browser it does not display — the browser downloads it instead.

Q. What is the MIME type of .fb2?

application/x-fictionbook+xml. The first half, application, names the broad kind; the second half, x-fictionbook+xml, names the exact format. It starts with x-, which means it was never registered as a standard.

Q. Can I convert a .fb2 file to another format?

Yes — open it and re-save through a converter. Renaming alone changes only the label; the bytes stay put, and programs that check the real format may refuse to open it.

Q. My .fb2 file will not open.

First check that Calibre is installed. If it still fails, the download may have been cut short, or the file may only be named .fb2 while holding a different format inside.

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