| Extension | Type | Category | Application or Description |
|---|
| .$$$ | ???? | Special | Temporary file |
| .••_ | ???? | Special | Windows installation, often compressed (• = any character) |
| .1st | TEXT | Word processing | Text Readme |
| .3df | 3DMF | 3D Image | Classic Mac OS QuickDraw 3D metafile |
| .3dmf | 3DMF | 3D Image | Classic Mac OS QuickDraw 3D metafile |
| .3ds | ???? | 3D Image | 3D Studio |
| .3g2 | ???? | Special | 3G Phone Protocol 2 (3GPP2) for audio, video and text to phones |
| .3gp | ???? | Special | 3G Phone Protocol (3GPP) for audio, video and text to phones |
| .509 | cert | Security | Digital certificate |
| .669 | 6669 | Music | Composer 669/Unis Composer MOD file |
| .8bf | 8BFM | Graphic | Photoshop plug-in |
| .8med | STrk | Music | Amiga OctaMed |
| .8sv | 8SVX | Sound | Amiga Interchange File Format (IFF) 8-bit mono sound |
| .8svc | 8SVX | Sound | Amiga Interchange File Format (IFF) 8-bit mono sound |
| .8svx | 8SVX | Sound | Amiga Interchange File Format (IFF) 8-bit mono sound |
| .a | TEXT | Programming | Assembly source |
| .a3d | AMAS | 3D Image | Amapi 3D |
| .aa | ???? | Sound | Audible Audio (AA) |
| .aam | ???? | Special | Authorware |
| .aas | ???? | Special | Authorware |
| .abc | TEXT | Music | Virtual Composer |
| .abs | TEXT | Word processing | Abstract from text document |
| .ac3 | ???? | Sound | AC-3 audio, used on DVD-Video |
| .acd | ???? | Sound | Sonic Foundry ACID sound sample |
| .acgi | APPL | Internet | AppleScript Common Gateway Interface (CGI) file |
| .adpcm | APCM | Sound | Intel Adaptive Differential Pulse Code Modulation (ADPCM) |
| .aex | eFKT | Special | Adobe After Effects plug-in |
| .afm | TEXT | Font | PostScript Adobe Font Metrics (AFM) |
| .ai | EPSF | Graphic or DTP | Adobe Illustrator simplified form of EPSF |
| .ai | EPSF | Movie | Adobe Illustrator animated sequence, simplified EPSF |
| .aif | AIFF | Sound | Audio Interchange File Format (AIFF) |
| .aifc | AIFC | Sound | Compressed AIFF (AIFF-C) |
| .aifc | AIFF | Sound | Compressed AIFF (AIFF-C) |
| .aiff | AIFF | Sound | Audio Interchange File Format (AIFF) |
| .aip | ARPI | Graphic | Adobe Illustrator Plug-in |
| .al | ALAW | Sound | A-law |
| .als | ???? | Sound | Ableton Live |
| .amc | ???? | 3D Image | Acclaim motion capture |
| .amf | ???? | Music | DMP Advanced MOD file |
| .ani | ANli | Movie | Atari Animated NeoChrome |
| .anim | ANli | Movie | Atari Animated NeoChrome |
| .apd | TEXT | Desktop publishing | Aldus printer description |
| .app | | Folder | Mac OS folder used as Application Program Package (APP) |
| .app | APPL | Special | Mac OS application |
| .arc | mArc | Archive | ARC compressed file, usually produced on a PC |
| .arj | BINA | Archive | ARJ compressed |
| .arr | ARR | Graphic | Amber ARR |
| .art | ART | Graphic | First Publisher |
| .as | ApSi | Internet | AppleSingle binary file containing one Classic Mac OS file |
| .asc | TEXT | Word processing | ASCII text |
| .ascii | TEXT | Word processing | ASCII text |
| .asf | ASF_ | Movie | Windows Media Active Streaming Format (ASF) |
| .asm | TEXT | Programming | Assembly source |
| .asp | TEXT | Internet | Active Server Pages (ASP) file for server-side code |
| .asf | TEXT | Movie | Microsoft Active Streaming Format (ASF) |
| .asf | ???? | 3D Image | Acclaim skeleton file |
| .asx | ASX_ | Movie | Windows Media format |
| .au | ULAW | Sound | µ-law format (Sun Audio) |
| .au.gsm | GSM | Sound | Coded speech for GSM mobile phone or Internet |
| .avi | VfW | Movie | Video for Windows (VfW) Audio Video Interleave (AVI) |
| .avr | ???? | Sound | Audio Visual Research (AVR) file |
| .bak | ???? | Word processing | Backup file, WordStar and others |
| .bar | BARF | Archive | Unix binary archive (BAR), obsolete |
| .bas | TEXT | Programming | BASIC source code |
| .bat | TEXT | Special | MS-DOS batch command (BAT) for PC |
| .bdf | TEXT | Font | Unix bitmap font |
| .bga | BMPf | Graphic | PC OS/2 bitmap |
| .bib | TEXT | Word processing | BibTex bibliography |
| .bin | MACB | Internet | MacBinary/BinHex 5, containing Classic Mac OS file |
| .binary | BINA | Special | Untyped binary data |
| .bld | BLD | Graphic | BLD format |
| .bmap | FFIL | Font | Classic Mac OS suitcase: bitmap screen font for PostScript font |
| .bmp | BMP | Graphic | Windows bitmap (BMP) |
| .bmp | BMPf | Graphic | Windows bitmap (BMP) |
| .bmp | BMPp | Graphic | Windows bitmap (BMP) |
| .boo | TEXT | Word processing | BOO encoded text |
| .bsc | ???? | Programming | Microsoft Source Browser database |
| .bst | TEXT | Word processing | BibTex style (BST) |
| .bub | BUB | 3D Image | IpixViewer Bubble (BUB) |
| .bup | ???? | Special | BUP backup for IFO file, used on DVD-Video |
| .bum | .bMp | Graphic | BUM bitmap format |
| .bvh | ???? | 3D Image | Bio Vision Hierarchy |
| .bw | .SGI | Graphic | Silicon Graphics SGI |
| .bz | Bzp2 | Archive | BZip2 |
| .bz2 | Bzp2 | Archive | BZip2 |
| .c | TEXT | Graphic | C source image dump |
| .c | TEXT | Programming | C source |
| .ca | cert | Security | Digital certificate |
| .cab | ???? | Archive | Microsoft Windows Cabinet (Windows installations) |
| .cdr | CD40 | Graphic | CorelDraw graphic |
| .cel | CEL | Graphic | KISS |
| .cer | cert | Security | Digital certificate |
| .cfm | TEXT | Internet | Cold Fusion Markup Language (CFML) file |
| .cfml | TEXT | Internet | Cold Fusion Markup Language (CFML) file |
| .chm | ???? | Special | LZW Compressed HTML (help file or eBook) |
| .cgi | APPL | Internet | Common Gateway Interface (CGI) file |
| .cgm | CGMm | Graphic | Harvard Computer Graphics Metafile (CGM) |
| .cicn | cicn | Graphic | Mac OS cicn Resource |
| .cin | ???? | 3D Image | Cineon |
| .class | TEXT | Programming | Java class |
| .clip | clpp | Graphic | Mac OS clipping |
| .clp | CLPp | Special | Windows clipboard |
| .clt | rawp | Special | Colour lookup table |
| .cmd | TEXT | Special | PC OS/2 batch file |
| .cmu | TEXT | Graphic | Unix CMU Window Manager dump |
| .com | PCFA | Special | MS-DOS executable binary file |
| .cp | TEXT | Programming | C++ source |
| .cpp | TEXT | Programming | C++ source |
| .cpt | CPT8 | Graphic | Corel PhotoPaint |
| .cpt | PACT | Archive | Compact Pro |
| .crt | cert | Security | Digital certificate |
| .css | TEXT | Internet | HTML Cascading Style Sheet (CSS) |
| .csv | TEXT | Spreadsheet/database | Comma Separated Values (CSV) |
| .ct | ..CT | Graphic | Scitex Continuous Tone (CT) |
| .cur | CUR | Graphic | Windows Cursor |
| .cut | Halo | Graphic | Dr Halo |
| .cvs | drw2 | Graphic | Canvas |
| .cwd | CWDB | Database | AppleWorks or ClarisWorks |
| .cwg | CWGR | Graphic | AppleWorks or ClarisWorks |
| .cwk | CWWP | Word processing | AppleWorks or ClarisWorks |
| .cwp | CWWP | Word processing | AppleWorks or ClarisWorks |
| .cwpb | ???? | Word processing | CopyWrite project |
| .cws | CWSS | Spreadsheet | AppleWorks or ClarisWorks |
| .dat | ???? | Special | Data (various formats) |
| .db | TEXT | Database | Microsoft Word |
| .dbf | F+DB | Database | DBase II or IIT |
| .dcm | ???? | Movie | Digital Imaging and Communications in Medicine (DICOM) |
| .dcr | FGDM | Movie | Director Shockwave |
| .dcx | DCXx | Graphic | PCX (ZSoft or PC Paintbrush) |
| .dd | DD01 | Archive | DiskDoubler compressed file |
| .dewf | DEWF | Sound | Sound Session Instrument file |
| .dfont | | Font | Mac OS X data-fork font |
| .dic | ???? | Special | Dictionary file |
| .dif | dvc! | Movie | Digital Video (DV) file |
| .dif | TEXT | Word processing | Document Interchange File (DIF): unformatted text |
| .dir | FGDM | Movie | Director Shockwave |
| .diz | TEXT | Word processing | BBS description |
| .djvu | ???? | Image | DjVu image or multi-page document |
| .dl | DL | Movie | DL animation |
| .dll | PCFL | Special | Windows Dynamically Linked Library (DLL) |
| .dll | shlb | Special | Mac OS Dynamically Linked Library (DLL) |
| .dmg | devi | Archive | Mac OS X device (disk) image |
| .dmg | devr | Archive | Mac OS X device (disk) image with raw data |
| .doc | TEXT | Word processing | ASCII text |
| .doc | WDBN | Word processing | Microsoft Word |
| .doc | W6BN | Word processing | Microsoft Word 6 |
| .doc | W8BN | Word processing | Microsoft Word 8 |
| .doo | ???? | Graphic | Atari DR Doodle |
| .dos | TEXT | Word processing | ASCII text |
| .dot | sDBN | Word processing | Microsoft Word template/stationery |
| .dox | ???? | Word processing | Multimate 4 |
| .drv | TEXT | Special | Device driver file |
| .dsm | ???? | Music | Dynamic Studio MOD file |
| .dtd | TEXT | Internet | Type definition file |
| .dts | ???? | Sound | Digital Theater System (DTS) audio, as used on DVD-Video |
| .dv | dvc! | Movie | Digital Video (DV) file |
| .dvi | ODVI | DTP | TeX DeVice Independent (DVI) file |
| .dwg | ???? | 3D Image | AutoCAD Drawing |
| .dwt | ???? | Internet | Dreamweaver Template |
| .dxf | ???? | 3D Image | AutoCAD Drawing Exchange File |
| .dxr | FGDM | Movie | Director Shockwave |
| .epp | ???? | 3D Image | Extended Pixel (EPix) Panorama file |
| .eps | EPSF | Graphic or DTP | Encapsulated PostScript File (EPSF) |
| .eps | EPSF | Movie | EPSF containing animated sequence |
| .epsf | EPSF | Graphic or DTP | Encapsulated PostScript File (EPSF) |
| .epsf | EPSF | Movie | EPSF containing animated sequence |
| .epx | ???? | 3D Image | Extended Pixel (EPix) file |
| .etd | ???? | Special | Adobe eBook Electronic Transfer Document (ETD) |
| .etx | TEXT | Word processing | SEText or Easy View text chapter |
| .evy | ENVD | Special | Envoy Viewer |
| .exe | PCFA | Special | MS-DOS Executable binary file (EXE) for Soft PC |
| .fam | FFIL | Font | Mac OS font suitcase (font family) |
| .far | ???? | Music | Farandole Composer MOD file |
| .faq | TEXT | Word processing | Frequently Asked Questions (FAQ) |
| .fax | TIFF | Graphic | Tagged Image Format File (TIFF) for fax |
| .fcache | ???? | Font | Mac OS X file collection cache |
| .fcp | ???? | Graphic | Atari Flash Colour Picture (FCP) compressed with RLE |
| .fdb | DBSE | Special | Portfolio |
| .fdf | FDF | Word processing | Acrobat Forms Data Format (FDF) |
| .fdp | ???? | Special | Portfolio |
| .fft | TEXT | Word processing | Document Content Architecture - Final Form Text (DCA-FFT) |
| .fh11 | ???? | Graphic | Freehand MX |
| .fh4 | ???? | Graphic | Freehand 4 |
| .fh5 | ???? | Graphic | Freehand 5 |
| .fh8 | ???? | Graphic | Freehand 8 |
| .fh9 | ???? | Graphic | Freehand 9 |
| .fhc | ???? | Graphic | Freehand |
| .fit | FITS | Graphic | Flexible Image Transport System (FITS) |
| .fla | BINA | Movie | Flash |
| .flc | FLI | Movie | FLIC animation, also known as Autodesk Animator File |
| .fli | FLI | Movie | FLIC animation, also known as Autodesk Animator File |
| .flm | ???? | Movie | Atari Animatic film format |
| .flv | ???? | Movie | Flash video format |
| .fm | FASL | DTP | FrameMaker |
| .fm | FMPR | Database | FileMaker Pro |
| .fm1 | ???? | Database | Lotus 1-2-3 version 2 |
| .fm3 | ???? | Database | Lotus 1-2-3 version 3 |
| .fmp | FMP3 | Database | FileMaker Pro |
| .fmx | iDLL | Database | FileMaker plug-in |
| .fon | ???? | Font | Windows FONT |
| .for | TEXT | Programming | FORTRAN source |
| .fp3 | FMP3 | Database | FileMaker Pro 3 or 4 |
| .fp5 | FMP5 | Database | FileMaker Pro 5 |
| .fpix | FPix | Graphic | FlashPix open standard for fast digital images |
| .fpix | FPX | Graphic | FlashPix open standard for fast digital images |
| .fpx | FPix | Graphic | FlashPix open standard for fast digital images |
| .fpx | FPX | Graphic | FlashPix open standard for fast digital images |
| .fsv | TEXT | Graphic | Unix Usenet FaceSaver |
| .fts | FITS | Graphic | Flexible Image Transport System (FITS) |
| .fxp | FFXP | Database | FoxPro Format File |
| .gcf | GC03 | Special | Graphing Calculator |
| .gdm | ???? | Music | General DigiMusic |
| .gem | GEM- | Graphic | Ventura Publisher GEM Metafile |
| .gif | GIFf | Graphic | Graphic Interchange File (GIFF) |
| .gif | GIFf | Movie | Animated Graphic Interchange File (GIFF) |
| .gl | GL | Movie | GRASP GL animation or image collection (MacAnim Viewer) |
| .grp | GRPp | Graphic | GRP format |
| .gsf | LWFN | Font | GhostScript font, not compatible with ATM |
| .gsm | GSM | Sound | Coded speech for GSM mobile phone or Internet |
| .gz | GZip | Archive | Gnu Zip |
| .h | TEXT | Programming | C Include file |
| .ham | ???? | Graphic | Amiga 24-bit IFF-HAM or Extra Halfbright IFF-HAM-E |
| .hcom | FSSD | Sound | SoundCap or SoundEdit |
| .help | | Special | Mac OS X help package |
| .hip | TEXT | Graphic | Unix HIPS format |
| .hlp | TEXT | Special | Help file |
| .hp | TEXT | Programming | C Include file |
| .hpgl | HPGL | Graphic | HP-GL/2 metafile |
| .hpp | TEXT | Programming | C Include file |
| .hqx | TEXT | Internet | BinHex 4, containing both forks of Classic Mac OS file |
| .hr | TR80 | Graphic | TRS-80 |
| .htm | TEXT | Internet | Hypertext Markup Language (HTML) file |
| .html | TEXT | Internet | Hypertext Markup Language (HTML) file |
| .hyp | TEXT | Special | Adobe hyphenation rules |
| .i3 | TEXT | Programming | Modula 3 interface |
| .ic1 | IMAG | Movie or Graphic | Atari Imagic IMAG 16-colour film or picture file |
| .ic2 | IMAG | Movie or Graphic | Atari Imagic IMAG 4-colour film or picture file |
| .ic3 | IMAG | Movie or Graphic | Atari Imagic IMAG monochrome film or picture file |
| .icc | prof | Special | ICC Mac OS ColorSync colour matching profile |
| .icm | prof | Special | ICC Mac OS ColorSync colour matching profile |
| .icn | ICO | Icon | Windows icon |
| .icns | ICNS | Icon | Mac OS X icon family |
| .ico | ICO | Icon | Windows Icon |
| .ics | ???? | Special | Apple iCal calendar file |
| .idx | TEXT | Special | Index (various formats) |
| .ief | IEF | Graphic | IEF |
| .iff | 8SVX | Sound | Amiga Interchange File Format (IFF) 8-bit mono sound |
| .iff | ILBM | Graphic | Amiga Interchange File Format IFF-ILBM |
| .iff | ???? | Graphic | Amiga Interchange File Format IFF-RGB8 |
| .iff | ???? | Graphic | Amiga Interchange File Format IFF-RGBN |
| .ifo | ???? | Special | IFO file, used on DVD-Video |
| .ilbm | ILBM | Graphic | Amiga Interchange File Format IFF-ILBM |
| .im1 | SUNn | Graphic | Sun raster 1-bit image |
| .im8 | SUNn | Graphic | Sun raster 8-bit image |
| .im24 | SUNn | Graphic | Sun raster 24-bit image |
| .image | dlmg | Archive | Apple Disk Copy disk image |
| .image | EIDI | Graphic | Electric Image |
| .imf | ???? | Music | Imago Orpheus |
| .img | ???? | Graphic | Atari STAD or XIMG formats |
| .img | dimg | Archive | Apple Disk Copy or ShrinkWrap disk image |
| .img | hdro | Archive | Apple Disk Copy disk image |
| .img | IMGg | Graphic | Ventura Publisher GEM bitmap IMG/XIMG |
| .img | KONT | Graphic | KONTRON |
| .img | roCd | Archive | ShrinkWrap disk image |
| .img | rohd | Archive | Apple Disk Copy or ShrinkWrap disk image |
| .img | rwCd | Archive | ShrinkWrap disk image |
| .inc | TEXT | Programming | CodeWarrior 'include' file |
| .indd | ???? | DTP | InDesign document |
| .ini | TEXT | Special | Initialisation (INI) file (Windows and other formats) |
| .inf | BINA | Special | Information file (various formats) |
| .ips | IPIX | 3D Image | Interactive Pictures (IpixViewer) |
| .ipx | IPIX | 3D Image | Interactive Pictures (IpixViewer) |
| .iss | ISS | Graphic | ISS |
| .it | IT | Music | Impulse Tracker MOD file (PlayerPRO) |
| .itl | ???? | Special | iTools Commands |
| .ivr | TEXT | 3D Image | Virtual Reality Markup Language (VRML) file |
| .jar | TEXT | Programming | Java resource, sometimes in form of ZIP file |
| .java | TEXT | Programming | Java source |
| .jfif | JPEG | Graphic | Joint Photographic Experts Group (JPEG) file |
| .jfx | TIFF | Graphic | JFax TIFF |
| .jhtml | TEXT | Internet | Similar to .shtml file, but containing Java |
| .jif | JIFf | Graphic | Joint Photographic Experts Group (JPEG) file |
| .jms | TEXT | Internet | Java Message Service, for Web site messages |
| .jpe | JPEG | Graphic | Joint Photographic Experts Group (JPEG) file |
| .jpeg | JPEG | Graphic | Joint Photographic Experts Group (JPEG) file |
| .jpg | JPEG | Graphic | Joint Photographic Experts Group (JPEG) file |
| .js | TEXT | Internet | JavaScript |
| .jsp | TEXT | Internet | Java Server Page, for dynamic pages at Web site |
| .jta | TEXT | Internet | Java Transaction API, for Web site transactions |
| .jvr | KinS | Database | 4th Dimension |
| .kext | ???? | Special | Mac OS X Kernal Extension file |
| .kar | Midi | Music | Karaoke Musical Instrument Data Interface (MIDI) file |
| .ksd | ???? | Special | Via Voice Keyboard Shortcuts Dictionaries Editor file |
| .lasso | ???? | Special | Lasso file |
| .latex | TEXT | Word processing | LaTex source file |
| .lbm | ILBM | Graphic | Amiga IFF-ILBM format |
| .ldi | ???? | Database | LDIF data, as used for address book |
| .ldif | ???? | Database | LDIF data, as used for address book |
| .lfa | DAN2 | 3D Image | Life Forms 3.x |
| .lha | LHA | Archive | LHarc |
| .lhz | LHA | Archive | LHarc |
| .lib | ???? | Special | Library (various formats) |
| .liv | ???? | Movie | Live Motion |
| .lnk | ???? | Special | Windows Linker shortcut file |
| .log | ???? | Special | Log file (various formats) |
| .logo | WBMP | Graphic | LOGO |
| .loop | ???? | Sound | Apple Soundtrack/GaragBand audio loop |
| .lproj | | Folder | Mac OS X language project folder |
| .lwf | lwfF | Graphic | LuraWave |
| .lwo | ???? | 3D Image | Lightwave object file |
| .m15 | ???? | Music | 15-instrument Amiga MOD file |
| .m15 | MPEG | Movie | Motion Picture Experts Group (MPEG-1) file |
| .m1a | MPEG | Movie | Motion Picture Experts Group (MPEG-1) file |
| .m1s | MPEG | Movie | Motion Picture Experts Group (MPEG-1) file |
| .m1v | MPEG | Movie | Motion Picture Experts Group (MPEG-1) IPB video |
| .m2 | TEXT | Programming | Modula 2 source |
| .m2s | MPG2 | Movie | Motion Picture Experts Group (MPEG-2) file |
| .m2v | MPG2 | Movie | Motion Picture Experts Group (MPEG-2) IPB video (DVD-Video) |
| .m3 | TEXT | Programming | Modula 3 source |
| .m3u | PNRA | Sound | RealPlayer |
| .m4a | ???? | Sound | MPEG-4 Advanced Audio Coding (AAC) file |
| .m75 | MPEG | Movie | Motion Picture Experts Group (MPEG-1) file |
| .mac | PICT | Graphic | Mac OS PICT |
| .mac | PNTG | Graphic | MacPaint |
| .mac | TEXT | Word processing | Classic Mac OS text |
| .mad | MADC | Music | MADC (PlayerPRO) |
| .madf | MADF | Music | MADF (PlayerPRO) |
| .madh | MADH | Music | MADH (PlayerPRO) |
| .madi | MADI | Music | MADI (PlayerPRO) |
| .mak | ???? | Programming | Microsoft project |
| .mak | TEXT | Special | Makefile |
| .map | ???? | Special | Program Link Map file |
| .mbd | ???? | Special | Multimedia Builder (MMBuilder) Document |
| .mbm | MBM | Graphic | PSION 5 Organiser file |
| .mbox | | Special | Mac OS X Mail mailbox package |
| .mcd | ???? | 3D Image | VectorWorks |
| .mcp | MMPr | Programming | Mac OS CodeWarrior project |
| .mcw | WDBN | Word processing | Word (Mac) |
| .mdp | ???? | Programming | Microsoft project |
| .mdz | MDZ | Music | x-Zipped MOD file (PlayerPRO) |
| .me | TEXT | Word processing | Read Me text |
| .med | MED | Music | Music Editor/OctaMED MED format (PlayerPRO) |
| .mem | BINA | Special | PC MS-DOS DBase Memory file |
| .mf | TEXT | Font | Metafont |
| .mgr | TEXT | Graphic | Unix MGR Window Manager dump |
| .mid | Midi | Music | MIDI sequence |
| .midi | Midi | Music | MIDI sequence |
| .mif | TEXT | Special | FrameMaker Metafile (MIF) |
| .mim | TEXT | Internet | MIME mail message coded using Base 64 |
| .mime | TEXT | Internet | MIME mail message coded using Base 64 |
| .ml | TEXT | Programming | ML source file |
| .mlp | ???? | Special | MacLinkPlus Print Capture file |
| .mmf | MMMF | Music | Meditor |
| .mno | ???? | Special | Metafile Note file |
| .mod | Strk | Music | Amiga Sound Tracker music module (MOD) (Player PRO) |
| .mol | TEXT | Special | MDL Molfile |
| .moov | MooV | Movie | QuickTime movie |
| .mov | MooV | Movie | QuickTime movie |
| .mp1 | MPEG | Sound | MPEG-1 |
| .mp2 | MPEG | Movie | MPEG-1 |
| .mp3 | MP3 | Sound | MPEG Layer-3 (MP3) |
| .mp3 | MPG3 | Sound | MPEG Layer-3 (MP3) |
| .mp3 | Mp3 | Sound | MPEG Layer-3 (MP3) |
| .mp4 | mpg4 | Movie | MPEG-4, also used for various multimedia material |
| .mpa | MPEG | Movie | MPEG-1 |
| .mpe | MPG2 | Movie | MPEG-2 (DVD-Video discs) |
| .mpeg | MPEG | Movie | MPEG-1 |
| .mpeg | MPG2 | Movie | MPEG-2 (DVD-Video discs) |
| .mpg | MPEG | Movie | MPEG-1 |
| .mpg | MPG2 | Movie | MPEG-2 (DVD-Video discs) |
| .mpga | MPEG | Sound | MPEG audio |
| .mpm | MPEG | Movie | MPEG-1 |
| .mpv | MPEG | Movie | MPEG-1 |
| .msi | ???? | Special | Microsoft Installer file |
| .msp | MSPp | Graphic | Microsoft Paint |
| .mtm | MTM | Music | MultiTracker MOD file (MultiMOD) |
| .mtv | ???? | 3D Image | Raytrace MTV format |
| .mus | DHAR | Music | Melody Assistant |
| .mvh | MooV | Movie | QuickTime movie |
| .mw | MW2D | Word processing | MacWrite II |
| .mwd | MBBT | Word processing | Mariner Write Document |
| .mwii | MW2D | Word processing | MacWrite II |
| .ndx | diDX | Movie | Director index file |
| .neo | NeoC | Graphic | Atari NeoChrome format |
| .nff | ???? | Graphic | Nikon raw format used in cameras |
| .nfo | TEXT | Word processing | Information text |
| .ngg | NGGC | Graphic | Mobil Phone |
| .nib | | Special | Mac OS X Interface Builder file (XML) used in APP |
| .nol | NOL | Graphic | Mobil Phone |
| .nsl | pref | Special | Network Services preferences |
| .nst | Strk | Music | Amiga music module (MOD) format (Player PRO) |
| .nxt | NeXT | Sound | µ-law format (NeXT) |
| .o | ???? | Programming | Object library |
| .obj | PCFL | Programming | Compiled object file (OBJ) |
| .obj | ???? | 3D Image | Alias Wavefront object file |
| .oda | ODIF | Special | ODA document |
| .okt | OKTA | Music | Oktalyzer MOD file (Player PRO) |
| .ogg | OggS | Sound | Ogg Vorbis |
| .otf | sfnt | Font | OpenType scalable font |
| .osax | osax | Special | Mac OS X AppleScript scripting addition |
| .out | BINA | Special | Binary output file (various formats) |
| .ovl | PCFL | Special | PC MS-DOS or Windows overlay (OVL) |
| .ovr | ???? | Special | Program overlay |
| .p | TEXT | Programming | Pascal source |
| .p12 | PK12 | Security | Keychain Access key exchange file |
| .p7c | PK07 | Security | Keychain Access digital certificate |
| .p7m | PK07 | Security | Keychain Access cryptographic message |
| .p7s | PK07 | Security | Keychain Access digital signature |
| .pac | STAD | Graphic | Atari STAD |
| .pal | TEXT | Graphic | ASCII PAL image |
| .pas | TEXT | Programming | Pascal source |
| .pax | ???? | Archive | Mac OS X file pack |
| .pbm | PPGM | Graphic | Unix portable bitmap |
| .pc | TEXT | Word processing | PC text |
| .pc1 | Dega | Graphic | Atari Degas compressed |
| .pc2 | Dega | Graphic | Atari Degas compressed |
| .pc3 | Dega | Graphic | Atari Degas compressed |
| .pcc | PCXx | Graphic | PCX (ZSoft or PC Paintbrush) |
| .pcm | ???? | Sound | PCM audio, used on DVD-Video |
| .pcs | PICS | Movie | Mac OS PICT sequence |
| .pct | PICT | Graphic | Mac OS PICT image |
| .pcx | PCXx | Graphic | PCX/SCR (ZSoft or PC Paintbrush) |
| .pcx | PICT | Graphic | Photoshop |
| .pdb | **** | Special | PalmOS database (HotSync) |
| .pdb | KSic | Graphic | Tiny Viewer |
| .pdb | MkCF | Graphic | MonkeyCard |
| .pdb | MkLG | Graphic | MonkeyLogo |
| .pdb | PDB | Graphic | FireViewer |
| .pdb | TEXT | Graphic | Brookhaven |
| .pdb | TlPt | Graphic | TealPaint |
| .pdf | PDF | Desktop publishing | PDF (Acrobat) |
| .pdx | TEXT | Desktop publishing | PageMaker printer description |
| .pf | CSIT | Security | Aladdin Private File (PF) document |
| .pf | prof | Special | Mac OS ColorSync colour matching profile |
| .pfa | TEXT | Font | Type 1 PostScript font |
| .pfb | BINA | Font | Type 1 PostScript font |
| .pfm | BINA | Font | Type 1 PostScript font metrics |
| .pfr | TEXT | Font | TrueDoc font |
| .pgc | PGCF | Graphic | Atari Portfolio |
| .pgm | PPGM | Graphic | Unix portable greymap format |
| .pgp | pgPR | Security | PGP signer key file (PGPkeys) |
| .php | TEXT | Internet | PHP file for server-side code |
| .pi1 | Dega | Graphic | Atari Degas |
| .pi2 | Dega | Graphic | Atari Degas |
| .pi3 | Dega | Graphic | Atari Degas |
| .pic | ???? | Graphic | Lotus vector format |
| .pic | PICT | Graphic | Mac OS PICT image |
| .pic | ???? | Graphic | Pictor, not compatible with Lotus |
| .pic | PSIO | Graphic | PSION Organiser file |
| .pic | SOFT | Graphic | SoftImage |
| .pics | PICS | Movie | Mac OS PICT sequence |
| .pict | PICT | Graphic | Mac OS PICT image |
| .pif | ???? | Special | Windows Program Information File (PIF) |
| .pih | PICT | Graphic | Mac OS PICT image |
| .piq | PICT | Graphic | Mac OS PICT image |
| .pit | PIT | Archive | PackIt |
| .pix | ???? | 3D Image | Pixels 3D |
| .pkg | HBSF | Archive | AppleLink Package containing Classic Mac OS files |
| .pkg | | Special | Mac OS X installation package |
| .pkg | pkg | Special | Newton personal organiser package |
| .pl | TEXT | Programming | Perl script (Unix) |
| .plist | | Special | Mac OS X Property List (PLIST) in XML, as used in APP (package) |
| .plg | ???? | Special | Plug-in (various formats) |
| .pls | PLS | Sound | Play list (RealPlayer and others) |
| .plt | HPGL | Graphic | HP GL/2 format |
| .plugin | | Special | Mac OS X Plug-in |
| .pm | PMpm | Graphic | XV bitmap |
| .pm | TEXT | Programming | Pearl module (MacPearl) |
| .pm3 | ALB3 | Desktop publishing | PageMaker 3 |
| .pm4 | ALB4 | Desktop publishing | PageMaker 4 |
| .pm5 | ALB5 | Desktop publishing | PageMaker 5 |
| .pnc | **** | Special | PalmOS application (HotSync) |
| .png | PNGf | Graphic | Portable Network Graphic (PNG) |
| .pnt | PNTG | Graphic | MacPaint or SuperPaint |
| .pntg | PNTG | Graphic | MacPaint or SuperPaint |
| .ppd | TEXT | Desktop publishing | Printer description (PageMaker) |
| .ppm | PPGM | Graphic | Unix portable bitmap (PBM), PGM or pixmap (PPM) |
| .pps | ???? | Special | PowerPoint slide show |
| .ppt | SLD3 | Special | PowerPoint presentation |
| .pqa | **** | Special | PalmOS application (HotSync) |
| .pqh | PICT | Graphic | Mac OS PICT image |
| .pr2 | ???? | Special | Persuasion Windows file |
| .prc | **** | Special | PalmOS application (HotSync) |
| .prg | ???? | Special | dBase Program file |
| .prg | BINA | Special | MS-DOS application program |
| .prj | MMPr | Programming | Mac OS CodeWarrior project |
| .prn | TEXT | Database | Printer output file, usually CSV |
| .ps | TEXT | Graphic or DTP | PostScript document |
| .psd | 8BPS | Graphic | Photoshop |
| .psw | ???? | Word processing | Pocket Word document (Pocket PC) |
| .pt4 | ALT4 | Desktop publishing | PageMaker 4 template |
| .pt5 | ALT5 | Desktop publishing | PageMaker 5 template |
| .pub | PUBF | Desktop publishing | PageMaker 2 |
| .pwi | ???? | Special | Pocket PC Notes document |
| .px | EPSF | Graphic | Photoshop EPSF |
| .pxr | PXR | Graphic | Photoshop pixar (PXR) |
| .pxr | ???? | 3D Image | Pixar |
| .py | TEXT | Programming | Python script (Unix) |
| .qcp | celp | Sound | QUALCOMM PureVoice |
| .qdv | QDVf | Graphic | QDV format |
| .qif | ???? | Special | Quicken Interchange Format (QIF) for financial data |
| .qif | qtif | Graphic | QuickTime Image |
| .qrt | ???? | 3D Image | Raytrace QRT format |
| .qt | MooV | Movie | QuickTime movie (deprecated extension) |
| .qti | qtif | Graphic | QuickTime Image (PictureViewer) |
| .qtif | qtif | Graphic | QuickTime Image (PictureViewer) |
| .qtl | qtlk | Movie | QuickTime Player movie |
| .qxd | XDOC | Desktop publishing | QuarkXpress document |
| .qxp | ???? | Desktop publishing | QuarkXpress |
| .qxt | XTMP | Desktop publishing | QuarkXpress template |
| .r | TEXT | Programming | Mac OS Rez source (MPW) |
| .ra | PNRA | Sound | Real Audio |
| .ram | PNRA | Sound | Real Audio |
| .rar | RARf | Archive | MacRAR |
| .ras | SUNn | Graphic | Sun raster image |
| .raw | RAW | Graphic | RAW image data (various formats) |
| .readme | TEXT | Word processing | Read Me |
| .rf | SUNn | Graphic | Sun raster image |
| .rf | PNRA | Real-time streaming | RealFlash clip (RealPlayer) |
| .rft | TEXT | Word processing | DCA - Revisable Form Text (DCA-RFT) |
| .rgb | .SGI | Graphic | Silicon Graphics SGI |
| .rgba | .SGI | Graphic | Silicon Graphics SGI |
| .rib | TEXT | 3D Image | Renderman 3D |
| .rif | RIFF | Graphic | Raster Image File Format (RIFF) (Letraset Imagestudio) |
| .rix | RIX3 | Graphic | ColoRIX or EGAPaint |
| .rjs | PNRA | Real-time streaming | RealSystem skin (RealPlayer) |
| .rla | ???? | 3D Image | Alias Wavefront SDSC raster image file |
| .rle | RLE | Graphic | Run Length Encoding (RLE) or C-RLE compressed file |
| .rm | PNRA | Real-time streaming | RealMedia audiovisual file (RealPlayer) |
| .rme | TEXT | Word processing | Read Me text |
| .rmf | RMF | Desktop publishing | Acrobat Rights Media File (RMF) |
| .rmf | ???? | Music | Beatnik Rich Music Format (RMF) |
| .rmj | PNRA | Real-time streaming | RealMedia clip (RealPlayer) |
| .rmm | PNRA | Real-time streaming | RealPlayer |
| .rmp | RMP | Real-time streaming | RealJukebox Music Package (RealPlayer) |
| .rmx | PNRA | Real-time streaming | RealSystem Secure Media Clip (RealPlayer) |
| .rnx | PNRA | Real-time streaming | RealPlayer |
| .rp | PNRA | Real-time streaming | RealPix clip (RealPlayer) |
| .rpf | ???? | 3D Image | RPF |
| .rpl | FRL! | Real-time streaming | Replica |
| .rpm | PNRA | Real-time streaming | RealPlayer plug-in |
| .rpm | | Special | Linux Red Hat Package Manager file |
| .rs | SUNn | Graphic | Sun raster image |
| .rsc | rsrc | Programming | Mac OS Resource file (ResEdit) |
| .rsrc | rsrc | Programming | Mac OS Resource file (ResEdit) |
| .rss | TEXT | Internet | Really Simple Syndication (RSS) XML file |
| .rt | PNRA | Real-time streaming | RealText clip (RealPlayer) |
| .rtf | RTF | Graphic | Rich Text Format (RTF) image |
| .rtf | TEXT | Word processing | Rich Text Format (RTF) |
| .rtfd | | Folder | Mac OS X folder containing RTF files and graphics |
| .rts | RTSP | Real-time streaming | RTSP stream descriptor file (QuickTime) |
| .rtsp | RTSP | Real-time streaming | RTSP stream descriptor file (QuickTime) |
| .rtx | TEXT | Word processing | Rich text |
| .rv | PNRA | Real-time streaming | RealVideo clip (RealPlayer) |
| .rzi | ???? | 3D Image | REALVIZ ImageModeler 3 |
| .s3m | S3M | Music | ScreamTracker 3 MOD file (S3M) (PlayerPRO) |
| .sam | TEXT | Word processing | AmiPro |
| .sbr | ???? | Programming | Microsoft Source Browser support file |
| .scc | MSX | Graphic | MSX format |
| .scg | RIX3 | Graphic | ColoRIX or EGAPaint |
| .sci | RIX3 | Graphic | ColoRIX or EGAPaint |
| .scp | **** | Special | PalmOS application (HotSync) |
| .scp | RIX3 | Graphic | ColoRIX or EGAPaint |
| .scpt | osas | Special | Mac OS X compiled AppleScript script |
| .scr | osas | Special | Mac OS compiled AppleScript script |
| .scr | RIX3 | Graphic | ColoRIX or EGAPaint |
| .scr | ???? | Programming | DOS Debug source file |
| .scr | ???? | Special | Windows screen saver file |
| .scu | RIX3 | Graphic | ColoRIX or EGAPaint |
| .sd | SFIL | Sound | Sound Designer |
| .sd2 | Sd2f | Sound | Sound Designer II |
| .sdes | Sd2f | Sound | Sound Designer II |
| .sdp | SDP | Real-time streaming | Scalable multicast stream descriptor |
| .sea | APPL | Archive | Self-extracting archive (SEA) (various formats) |
| .sf | IRCM | Sound | IRCAM mono or stereo format (SoundHack) |
| .sf2 | ???? | Sound | Creative Labs Soundfont 2 sound sample bank |
| .sfil | sfil | Sound | Classic Mac OS System sound |
| .sgi | .SGI | Graphic | Silicon Graphics SGI |
| .sgm | TEXT | Special | Standard Generalised Markup Language (SGML) |
| .sgml | TEXT | Special | Standard Generalised Markup Language (SGML) |
| .sh | TEXT | Programming | Shell Archive (SHAR) script (Unix) |
| .sha | TEXT | Programming | Shell Archive (SHAR) script (Unix) |
| .shar | TEXT | Programming | Shell Archive (SHAR) script (Unix) |
| .shk | ???? | Movie | Apple Shake video compositing file |
| .shl | shlb | Special | Mac OS shared library file, sometimes as a plug-in |
| .shlb | shlb | Special | Mac OS shared library file, sometimes as a plug-in |
| .shp | SHPp | Graphic | Printmaster icon library |
| .shr | ???? | Graphic | Apple IIGS Super-HiRes format |
| .shr | TEXT | Programming | Shell Archive (SHAR) script (Unix) |
| .shs | TEXT | Programming | Shell Archive scrap (Unix) |
| .shtm | TEXT | Internet | HTML file, processed by server before downloading |
| .shtml | TEXT | Internet | HTML file, processed by server before downloading |
| .sid | sidf | Graphic | MrSID |
| .sit | SIT5 | Archive | StuffIt 5.x or higher |
| .sit | SITD | Archive | StuffIt 4.x or lower |
| .sithqx | TEXT | Archive | Binhexed StuffIt file |
| .sitx | ???? | Archive | StuffIt Mac OS X format |
| .six | SIXE | Graphic | SIXEL |
| .sk | TEXT | Spreadsheet | Symbolic Link (SYLK) |
| .skp | ???? | 3D Image | SketchUp |
| .slk | TEXT | Spreadsheet | Symbolic Link (SYLK) |
| .smf | Midi | Music | Standard MIDI File (SMF) |
| .smi | .SMI | Special | SMIL |
| .smi | APPL | Archive | Self-mounting image (Disk Copy or ShrinkWrap) |
| .smil | .SMI | Special | SMIL |
| .snd | BINA | Sound | Generic format (SoundApp) |
| .snd | ULAW | Sound | µ-law format (Sun Audio) |
| .snd | NeXT | Sound | µ-law format (NeXT) |
| .spc | ???? | Sound | SPC audio, used on DVD-Video |
| .spc | Spec | Graphic | Atari Spectrum 512 image |
| .spl | BINA | Movie | FutureSplash Player |
| .sr | SUNn | Graphic | Sun raster |
| .src | issp | Internet | Sherlock Internet search site (Mac OS) |
| .srd | APPL | Special | Self-reading document (application) |
| .ssm | PNRA | Real-time streaming | Standard Streaming Metafile (SSM) (RealPlayer) |
| .stg | TDAT | Programming | CodeWarrior settings file |
| .stk | Stak | Special | HyperStudio stack |
| .stm | TEXT | Internet | HTML file, processed by server before downloading |
| .stm | ???? | Music | ScreamTracker 2 MOD file (STM) (PlayerPRO) |
| .stn | ???? | Image | Genuine Fractals (GF) compressed image |
| .stx | ???? | Music | STMIK 0.2 |
| .sty | TEXT | DTP | TeX style (OzTex) |
| .sty | ???? | Word processing | Word style |
| .suit | FFIL | Font | Classic Mac OS font suitcase |
| .sun | SUNn | Graphic | Sun raster |
| .sup | SCRN | Graphic | Classic Mac OS startup screen |
| .svg | svg | Graphic | Scalable Vector Graphics (SVG) (Illustrator) |
| .svgz | svgz | Graphic | Scalable Vector Graphics (SVG) (Illustrator) |
| .svx | 8SVX | Sound | Amiga Interchange File Format (IFF) 8-bit mono sound |
| .swf | SWFL | Movie | Macromedia Shockwave Flash (SWF) |
| .syk | TEXT | Spreadsheet | Symbolic Link (SYLK) format |
| .syl | TEXT | Spreadsheet | Symbolic Link (SYLK) format |
| .sylk | TEXT | Spreadsheet | Symbolic Link (SYLK) format |
| .sys | BINA | Special | PC MS-DOS system file |
| .t1 | FFIL | Font | Classic Mac OS font suitcase for related PostScript Type 1 font |
| .tar | TARF | Archive | Unix tape archive (TAR), uncompressed |
| .targa | TPIC | Graphic | Targa Truevision (TGA) |
| .taz | ZIVU | Archive | Unix tape archive (TAR), Lempel-Ziv compressed |
| .tbz | Bzp2 | Archive | Unix tape archive (TAR), BZip2 compressed |
| .tcl | TEXT | Programming | Tickle |
| .tdf | TEXT | Spreadsheet/database | Tab-delimited text, equivalent to TSV |
| .tdi | ???? | 3D Image | Maya 3D image file |
| .tdm | ???? | Sound | TDM Plug-in for audio applications |
| .tex | TEXT | DTP | TeX source (OzTex) |
| .texi | TEXT | DTP | TeX source (OzTex) |
| .texinfo | TEXT | DTP | TeX source (OzTex) |
| .text | TEXT | Word processing | ASCII text |
| .tga | TPIC | Graphic | Targa Truevision (TGA) |
| .tgz | GZip | Archive | Unix tape archive (TAR), GZip compressed |
| .tif | TIFF | Graphic | Tagged Image Format File (TIFF) |
| .tiff | TIFF | Graphic | Tagged Image Format File (TIFF) |
| .tiff | TIF | Graphic | Tagged Image Format File (TIFF) |
| .tiff | tiff | Graphic | Tagged Image Format File (TIFF) |
| .tiff | tif | Graphic | Tagged Image Format File (TIFF) |
| .tiga | TPIC | Graphic | Targa Truevision (TGA) |
| .tfm | ???? | Font | TeX font |
| .tkn | ???? | Internet | E-mail token of file for later download |
| .tmp | ???? | Special | Template (various formats) |
| .tmpl | ???? | Special | Template (various formats) |
| .tny | TINY | Graphic | Atari TINY bitmap format |
| .tpic | TPIC | Graphic | Targa Truevision (TGA) |
| .tsv | TEXT | Spreadsheet/database | Tab Separated Values (TSV) |
| .tt | FFIL | Font | Classic Mac OS font suitcase (TrueType font family) |
| .ttc | ttcf | Font | TrueType font collection |
| .ttf | FFIL | Font | Classic Mac OS font suitcase (TrueType font family) |
| .ttf | sfnt | Font | Windows TrueType scalable font |
| .tx8 | TEXT | Word processing | 8-bit text |
| .txt | TEXT | Graphic | ASCII image |
| .txt | TEXT | Word processing | ASCII text |
| .ul | ULAW | Sound | µ-Law (Sun Audio) |
| .ulaw | ULAW | Sound | µ-Law (Sun Audio) |
| .ult | ???? | Music | Ultratracker MOD file |
| .ulw | ULAW | Sound | µ-Law (Sun Audio) |
| .url | AURL | Internet | Uniform Resource Locator (URL) bookmark |
| .usr | ???? | Security | User certificate |
| .uu | TEXT | Archive | Unix-to-Unix encoded file (UUencoded) |
| .uue | TEXT | Archive | Unix-to-Unix encoded file (UUencoded) |
| .vcf | ???? | Special | Virtual business card (vCard) |
| .vcs | ???? | Special | Virtual calendar (vCal) |
| .vef | ???? | Special | Virtual event file (Now Up-to-Date) |
| .vfb | VFB1 | Font | FontLab font |
| .vff | VFFf | Graphic | DESR VFF greyscale format |
| .vfw | VfW | Movie | Video For Windows (VfW, also known as AVI) |
| .view | IndX | Word processing | Easy View index |
| .vga | BMPp | Graphic | PC OS/2 bitmap |
| .vgs | ???? | Music | Voice of the Goat Cactus studio file |
| .viv | ???? | Movie | Vivo |
| .vob | ???? | Movie | Video Object (VOB), for recording video onto DVD |
| .voc | VOC | Sound | PC Sound Blaster VOC format |
| .vpb | VPB | Graphic | QUANTEL |
| .vrml | TEXT | 3D Image | Virtual Reality Markup Language (VRML) file |
| .vsd | ???? | Graphic | Visio drawing |
| .vtc | ???? | Movie | MPEG-4 (e-Vue Image Viewer) |
| .w3d | ???? | 3D Image | Director 3D and Shockwave 3D |
| .w51 | .WP5 | Word processing | PC WordPerfect 5.1 |
| .w61 | WPD3 | Word processing | Mac WordPerfect 6.1 |
| .waf | WAFF | Internet | Internet Explorer Web Archive File (WAF) |
| .war | ???? | Internet | Web Application Archive |
| .wav | WAVE | Sound | Windows WAVE format |
| .wax | ASX_ | Sound | Windows Media format |
| .wbd | ???? | Database | Works database |
| .wbmp | WBMP | Graphic | Wireless Bitmap for WML and WAP mobile phones |
| .wk1 | XLBN | Spreadsheet | Lotus 2 |
| .wk3 | XLBN | Spreadsheet | Lotus 3 (3D) |
| .wk4 | ???? | Spreadsheet | Lotus 4 |
| .wks | XLBN | Spreadsheet | Lotus 1 |
| .wm | ASF_ | Movie | Windows Media (WM) format |
| .wma | ASF_ | Sound | Windows Media (WM) format |
| .wmd | WMD_ | Movie | Windows Media (WM) format |
| .wmf | .WMF | Graphic | Windows Metafile (WMF) |
| .wmf | WMF | Graphic | Windows Metafile (WMF) |
| .wml | TEXT | Internet | Wireless Markup Language (WML) for WAP mobile phones |
| .wmp | ASF_ | Movie | Windows Media (WM) format |
| .wmv | ASF_ | Movie | Windows Media (WM) format |
| .wmx | ASX_ | Movie | Windows Media (WM) format |
| .wp | ???? | Word processing | OfficeWriter |
| .wp | WPD3 | Word processing | Mac WordPerfect 3.1 |
| .wp | .WP5 | Word processing | PC WordPerfect 5.1 |
| .wp4 | .WP4 | Word processing | PC WordPerfect 4.2 |
| .wp5 | .WP5 | Word processing | PC WordPerfect 5.x |
| .wp6 | .WP6 | Word processing | PC WordPerfect 6.x |
| .wpf | TEXT | Word processing | WordPerfect text |
| .wpg | WPGf | Graphic | WordPerfect graphic (WPG) |
| .wpl | ???? | Word processing | WPS-Plus VMS document |
| .wpm | WPD1 | Word processing | Mac WordPerfect |
| .wps | WDBN | Word processing | Works |
| .wq1 | ???? | Spreadsheet | Quattro Pro spreadsheet |
| .wrd | WDBN | Word processing | Word |
| .wri | WDBN | Word processing | Windows Microsoft Write |
| .wrk | ???? | Spreadsheet | Symphony |
| .wrl | TEXT | 3D Image | Virtual Reality Markup Language (VRML) file |
| .wrl | ???? | Spreadsheet | Symphony |
| .wrz | TEXT | 3D Image | Virtual Reality Markup Language (VRML) file |
| .ws | TEXT | Word processing | WordStar |
| .wve | PSI5 | Sound | PSION Organiser 5 sound file with EPOC 32 encoding |
| .wve | PSON | Sound | PSION Organiser 3 sound file with a-law encoding |
| .wvx | ASX_ | Movie | Windows Media format |
| .x-face | TEXT | Graphic | X-Face |
| .x10 | XWDd | Graphic | Unix X-Windows dump (XWD) |
| .x11 | XWDd | Graphic | Unix X-Windows dump (XWD) |
| .xbm | XBM | Graphic | Unix X-Windows bitmap (XBM) |
| .xdo | TEXT | Graphic | Unix Xerox Doodle Brush |
| .xfdf | XFDF | Desktop publishing | Acrobat Forms Data Format (FDF) in XML |
| .xib | | Special | Mac OS X Interface Builder file (XML) used to form APP |
| .xif | TIFF | Graphic | Tagged Image Format File (TIFF) for fax |
| .xja | TEXT | Internet | Embedded Java applet |
| .xja11 | TEXT | Internet | Embedded Java applet version 1.1 |
| .xja112 | TEXT | Internet | Embedded Java applet version 1.1.2 |
| .xjv | TEXT | Internet | Embedded JVM |
| .xl | XLS | Spreadsheet | Excel |
| .xla | ???? | Spreadsheet | Excel add-in macro |
| .xlc | XLC | Spreadsheet | Excel chart |
| .xlm | XLM4 | Spreadsheet | Excel 4 macro |
| .xls | XLS3 | Spreadsheet | Excel 3 |
| .xls | XLS5 | Spreadsheet | Excel 5 |
| .xlt | ???? | Spreadsheet | Excel template |
| .xlw | XLW5 | Spreadsheet | Excel 5 work space |
| .xm | XM | Music | FastTracker 2/Digital Tracker MOD file (PlayerPRO) |
| .xml | TEXT | Special | Extensible Markup Language (XML) file |
| .xmp | ???? | Special | Adobe Extensible Metadata Platform data in separate file |
| .xp | XDOC | Desktop publishing | QuarkXpress (XP) |
| .xpl | PNRA | Real-time streaming | Play list (RealPlayer) |
| .xpm | XPM | Graphic | Unix X-Windows pixmap (XPM) |
| .xtg | ???? | Desktop publishing | QuarkXpress tags file |
| .xwd | XWDd | Graphic | Unix X-Windows dump (XWD) |
| .xy | ???? | Word processing | XYWrite |
| .yenc | ???? | Archive | yEncode file (Usenet groups) |
| .yuv | .YUV | Graphic | Diskus YUV |
| .Z | ZIVU | Archive | Lempel-Ziv compressed Unix file |
| .z | ZIVU | Archive | Lempel-Ziv compressed Unix file |
| .zip | ZIP | Archive | PC Zip (PKZip) compressed file |
| .zoo | Zoo | Archive | Zoo |
|