File extensions start with character 'F'
| File Type | Category | File Format | |
|---|---|---|---|
| .f | Development Files | Fortran Source Code | |
| .f4f | Digital Video Files | Flash Video Fragment | |
| .f4v | Digital Video Files | Flash MP4 Video File | |
| .fa | Data Files | FASTA Formatted Sequence File | |
| .faq | Text Files | Frequently Asked Questions Document | |
| .fasta | Data Files | FASTA Sequence File | |
| .fat | Configuration Files | Zinf Theme File | |
| .fb2 | eBook Files | FictionBook 2.0 File | |
| .fbk | Backup Files | Microsoft Dynamics NAV Backup File | |
| .fbl | Text Files | CADfix Command Level Log File | |
| .fbm | Raster Graphics Files | Fuzzy Bitmap Image | |
| .fbp | Development Files | wxFormBuilder Project | |
| .fbr | Digital Video Files | FlashBack Screen Recording | |
| .fbrb | Game Files | Battlefield Bad Company 2 Data File | |
| .fbt | Configuration Files | ABBYY FineReader Document Options File | |
| .fbx | ArcView Files | Autodesk FBX Interchange File | |
| .fbz | Video Files | FlashBack Screen Recorder Movie | |
| .fcf | Text Files | Final Draft Converter File | |
| .fcl | Development Files | ForeUI Custom Library File | |
| .fd2 | Page Layout Files | PictureMate Borders File | |
| .fda | Audio Files | Dawn of War Audio File | |
| .fdb | Database Files | Portfolio Catalog | |
| .fdf | Text Files | Acrobat Forms Data Format | |
| .fdm | Microsoft Files | Exchange Forms Designer Form Message | |
| .fdr | Text Files | Final Draft Document | |
| .fds | Text Files | Final Draft Secure Copy | |
| .fdt | Text Files | Final Draft 5-7 Template | |
| .fdx | Text Files | Final Draft Document | |
| .fdxt | Text Files | Final Draft 8 Template | |
| .fes | Data Files | Fileless Occurrence Placeholder | |
| .fev | Audio Files | FMOD Audio Events File | |
| .ff | Description Files | Call of Duty 4 Fast File | |
| .ffd | Data Files | Flat File Descriptor | |
| .fff | Camera Photo Files | Hasselblad RAW Image | |
| .ffil | Font Files | Mac Font Suitcase | |
| .ffl | System Files | Find Fast Document List | |
| .ffo | System Files | Find Fast Document Properties Cache | |
| .fft | Text Files | Final Form Text File | |
| .ffwp | Data Files | FormsForWeb Packet | |
| .ffx | Configuration Files | After Effects Preset File | |
| .fid | Data Files | File Expander Engine Descriptions Database | |
| .fid | System Files | Microsoft Catalog Indexing Service File | |
| .fif | Vector Graphics Files | Fractal Image File | |
| .fil | Data Files | Files List Object File | |
| .file | Multiple Use Files | Generic Windows File | |
| .fla | Development Files | Adobe Flash Animation | |
| .flac | Codec Files | Free Lossless Audio Codec File | |
| .flame | Data Files | Fractal Flames File | |
| .flipchart | Flipchart Files | ActivInspire Flipchart File | |
| .flk | Data Files | Folder Lock File | |
| .fll | Data Files | FoxPro Dynamic-Link Library | |
| .flo | Data Files | iGrafx FlowCharter File | |
| .flow | Data Files | Expression SketchFlow Data File | |
| .flp | Adobe Files | FruityLoops Project | |
| .flr | Text Files | Flare Decompiled ActionScript File | |
| .flt | 3D Graphics Files | OpenFlight Scene Description File | |
| .flv | Digital Video Files | Flash Video File | |
| .flwa | Data Files | Folder Lock Wallet File | |
| .fm | Page Layout Files | FrameMaker Document | |
| .fmt | Configuration Files | FoxPro Format File | |
| .fmz | CAD Files | Form•Z Project File | |
| .fnbk | Data Files | Food Network Recipe Manager Data File | |
| .fnrecipes | Data Files | Food Network Recipe File | |
| .fo | Data Files | XSL-FO Form | |
| .folx | Data Files | Folx Download File | |
| .fon | Font Files | Generic Font File | |
| .fop | Data Files | InfoZoom Protected Data File | |
| .fox | Data Files | InfoZoom Data File | |
| .fpd | CAD Files | Front Panel Designer Project | |
| .fpk | Game Files | Civilization 4 Data File | |
| .fpsl | Data Files | FileMaker Pro Snapshot Link | |
| .fpt | Database Files | FileMaker Pro Database Memo File | |
| .framework | Development Files | Mac OS X Application Framework | |
| .frg | Audio Files | Sony Sound Forge Pro Project File | |
| .frl | Data Files | Electronic Form Loader File | |
| .frm | Database Files | MySQL Database Format File | |
| .frm | Development Files | Visual Basic Text Form | |
| .fro | Data Files | dBASE IV Compiled Report | |
| .frt | Text Files | FoxPro Report Memo | |
| .fsb | Audio Files | FMOD Sample Bank File | |
| .fsc | Data Files | Practical Scriptwriter File | |
| .fss | Data Files | Splitty Data Split File | |
| .ftm | Audio Files | FamiTracker Module | |
| .ftm | Data Files | Family Tree Maker for DOS File | |
| .ftw | Data Files | Family Tree Maker File | |
| .fwp | Web Files | Microsoft Expression Web Package | |
| .fxc | Development Files | FilePackager Configuration | |
| .fxp | Database Files | Adobe Flex Project File | |
| .fxp | Executable Files | FoxPro Compiled Program | |
| .fxp | Plug-in Files | VST Audio Plug-in | |
| .fzf | Audio Files | Casio FZ-1 Full Dump | |
| .fzz | CAD Files | Fritzing Shareable Project File |