If you are seeking information about file extensions, then you are in the right place at the right time.

Details of extension .fn

On this page, we're going to take a closer look at the .fn file extension.

We'll explain what exactly a .fn file format is and how you can use it. If you're interested in learning more details about this type of file, we'll show you where to find them. And if you ever need to convert .fn files into different formats, we'll give you some tips on how to do that too.

Let's see the 2 file formats associated with this file extension!


  1. STK Facility Networks File
  2. GCL Cross Referencing Data

We trust that our website will provide valuable information for you. If you have any questions, just ask!

STK Facility Networks File

fn file - STK Facility Networks File
The FN file belongs to the Data category and works with Systems Tool Kit, being used as a STK Facility Networks File. STK (Systems Tool Kit) is a physics-based software geometry engine that accurately displays and analyzes land, sea, air, and space assets in real or simulated time. The developer is still actively supporting the Systems Tool Kit, likely. Our data shows that Systems Tool Kit uses 26 more file types.
Application: Systems Tool Kit
Program name: -
Category: Data files
Mime-type: application/octet-stream
Related extensions:
.pe STK Planetary Ephemeris File
.wr STK Write Ups File
.rot STK Central Body Rotation File
.cd STK City Database Main File

GCL Cross Referencing Data

fn file - GCL Cross Referencing Data
The FN file belongs to the Development category and works with GNU Common Lisp, being used as a GCL Cross Referencing Data. GCL (GNU Common Lisp) is the GNU Project's Common Lisp compiler. The .fn file contains cross referencing information as well as information useful to the collection utilities in cmpnew/collectfn. The developer is still actively supporting the GNU Common Lisp, likely. Our data shows that GNU Common Lisp uses 2 more file types.
Application: GNU Common Lisp
Program name: -
Category: Development files
Mime-type: application/octet-stream
Related extensions:
.lsp Lisp Source Code
.vlx AutoLISP Visual LISP Executable

The .fn file extension might not only belong to a single type of file, there could be various kinds that use it. Keep in mind that files with the .fn extension may contain various content types. If you have helpful information about this extension, write to us!

Could someone have spelled the .fn file extension wrong?

In our database, we came across the following similar extensions:

.nf The Bro NetFlow Data
.fb DR-DOS Backup Data
.dn Adobe Dimension Model Data
.gn Apollo HDRU Image
.en English Language Info File
.bn NewsRoom Document

The .fn extension is frequently misused

People sometimes confuse the .fn filename extension. Based on the searches on our site, here are the most common misspellings from the past year.

rn (1), fb (1), dn (1), nf (1), en (1), bn (1), fm (1), tn (1), cn (1), fg (1)

Having trouble opening a .fn file?

If you want to open a .fn file on your computer, you just need to have the appropriate program installed. Incorrect settings for the .fn association can trigger this error.

Windows can't open this file:

File: example.fn

To open this file, Windows needs to know what program you want to use to open it. Windows can go online to look it up automatically, or you can manually select from a list of programs that are installed on your computer.

To change file associations:

  • Right-click a file with the extension whose association you want to change, and then click Open With.
  • In the Open With dialog box, click the program with which you want the file to open, or click Browse to locate the program that you want.
  • Select the Always use the selected program to open this kind of file check box.

Supported operating systems

Windows Server 2016/2019/2022, Windows 7, Windows 8, Windows 10, Windows 11, Linux, Mac OS X, macOS, iOS, Android