There are hundreds and hundreds of filename extensions and the  following list is by no means complete.  It will continually be expanded and refined.

If you find an error or would like to make an addition to the list, send your comments and suggestions to

  
  A back to the top
   A3M    Multimedia   Authorware Macintosh
   A3W    Multimedia   Authorware Windows
   AFM    ?            Adobe Font Metric 
   AI     Data         Adobe Illustrator
   AIF    Audio        Audio Interchange File
   ANI    Data         Animated Cursor
   APD    Data         Aldus Page Maker document
   AVI    Video        Audio Video Interface
   ASA    ?            ?
   ASP    Application  Application Service Provider
   ASP    Data         Application Server Pages
   AU     Audio        Sun Audio - the native UNIX audio file format

  
  B back to the top
   BAK    Text         Backup File
   BAT    Text         Batch File
   BIN    Data         Binary
   BMP    Raster       Windows Bitmap

  
  C back to the top
   C      Text         C programming source file
   CAB    Compression  Windows Cabinet file
   CFG    Data/Text    Configuration
   CGI    Application  Common Gateway Interface
   CGM    Meta         Computer Graphics Metafile
   CHM    ?            ?
   CHW    Text         Compiled HTML File
   CNT    ?            ?
   COM    Application  Command File
   CR2    Graphic      Canon RAW CR2
   CRW    Graphic      Canon RAW CRW
   CSS                 Cascading Style Sheet
   COR    ?            ?
   CUR    Data         Windows Cursor

  
  D back to the top
   DAT    Data         Data File
   DCR    Multimedia   Macromedia Director - Kodak RAW
   DB     Data         Paradox DataBase
   DBF    Data         dBase DataBase
   DIF    Data         Data Interchange Format
   DJV    Graphic      AT&T DjVu Image
   DLL    Application  Dynamic Linked Library
   DOC    Text         Microsoft Word
   DOT    Text         Microsoft Word Document Template
   DWG    Vector       AutoCAD Drawing
   DXF    Vector       AutoCAD Intermediate

  
  E back to the top
   EMF    Meta         Windows Enhaced Metafile
   EPS    Graphic      Encapsulated Post Script
   ESP    Meta         Encapsulated PostScript
   EXE    Application  Exectuable Application

  
  F back to the top
   F      Data         Paradox Form
   FLC    Animation    AutoDesk Animation
   FPX    Graphic      FlashPix

  
  G back to the top
   GID
   GIF    Raster       Graphics Interchange Format
   GZ     Compression  GZIP Compression Format

  
  H back to the top
   HLP    Text         Windows Help File
   HQX    Encoding     Mac Byte-Stream Encoded
   HTD    ?            ?
   HTML   Text         Hypertext Markup Language
   HTT    Text         Hypertext Template

  
  I back to the top
   ICL    Graphic      ICL
   ICN    Graphic      AT&T / Multigen
   ICO    Raster       Icon
   IFF    Graphic      Interchange File Format Image
   INC    Data         ASP INClude File
   INI    Text         Windows Initialization File

  
  J back to the top
   J2C    Graphic      JPEG 2000 Codestream
   J2K    Graphic      JPEG 2000 JP2 File
   JP2    Graphic      JPEG 2000 JP2 File
   JPC    Graphic      JPEG 2000 Codestream
   JPG    Raster       Joint Photographic Experts Group
   JPK    Graphic      JPEG 2000 JP2 File
   JPX    Graphic      JPEG 2000 JP2 File

  
  K back to the top
   none

  
  L back to the top
   LOG    Text/Data    Log File

  
  M back to the top
   MCW    Text         Macintosh Word Document
   MID    Audio        Musical Instrument Digital Interface
   MIDI   Audio        Musical Instrument Digital Interface
   MFD    ?            ?
   MOV    Video        QuickTime Movie
   MP2    Audio        MPEG Audio Layer II compressed audio
   MP3    Audio        MPEG Audio Layer III compressed audio
   MPG    Video        Motion Picture Experts Group
   MRW    Graphic      Konica Minolta RAW

  
  N back to the top
   NEF    Graphic      Nikon RAW File
   NTP    Data         Neato Lable File

  
  O back to the top
   OCX    ??           ??
   ORF    Graphic      Olympus RAW FIle

  
  P back to the top
   PAS    Data         Pascal
   PBM    Graphic      Portable Bitmap
   PCD    Graphic      Kodak Photo CD
   PCX    Raster       Windows Paintbrush
   PDF    Portable     Portable Document Format
   PEF    Graphic      Pentax RAW File
   PGM    Graphic      Portable Graymap
   PIC    Meta         Macintosh Picture
   PIF    Data         Windows
   PIX    Graphic      Alias PIX
   PNG    Raster       Portable Network Graphic
   PPM    Graphic      Portable Pixmap
   PPT    Slides       Microsoft PowerPoint Presentation
   PRN    Text         Printer
   PS     PostScript   ASCII PostScript File
   PSD    Graphic      PSD
   PSP    Graphic      Paint Shop Pro
   PST    Data         Microsoft Outlook 
   PWL    Text         Windows Password File
   PX     Data         Paradox Index

  
  Q back to the top
   QBW    Data         QuickBooks Data
   QDF    Data         Quicken Data
   QDT    Data         Quicken Data
   QSD    Data         Quicken Data

  
  R back to the top
   R      Data         Paradox Report
   RAF    Graphic      Fujifilm RAW File
   RAS    Raster       Sun Rasterfile
   RAW    Graphic      RAW File
   RGB    Raster       Silicon Graphics 24-Bit Color
   RMI    Audio        MIDI Sequence
   RTF    ?            Rich Text Format

  
  S back to the top
   SAM    Text         AmiPro document file
   SC     Data         Paradox Script
   SCR    Data         Windows Screen-Saver
   SEA    Compression  Self-Extracting Archive
   SHTML  Text         ?
   SIT    Compression  Stuffit Compressed Archive File
   SND    Audio        Macintosh Sound File
   SYS    Driver       Windows System File

  
  T back to the top
   TAX    Data         Turbo-Tax Data
   TGA    Raster       Truvision Targa 24-Bit
   TIF    Raster       Tagged Image File Format
   TTF    Font         True-Type Font
   TXT    Text         Raw, Unformatted Text

  
  U back to the top
   UDI    ?            ?
   URL    ?            ?
   USR    ?            ?
   UWL    ?            ?

  
  V back to the top
   VAL    Data         Paradox Value
   VBS    Text         Visual Basic Script
   VBW    Text         Visual Basic
   VBX    Text         Visual Basic
   VER    Data         Version File
   VID    ?            ?
   VIR    Data         Virus Infected File
   VIV    Video        Compressed Live Video
   VRS    ?            ?
   VXD    Driver       Windows Virtual Device Driver

  
  W back to the top
   WAV    Audio        Windows Audio-Visual
   WB1    Data         QuatroPro Spreadsheet
   WMA    Audio        Windows Medio Audio compressed audio
   WMF    Graphics     Windows Meta File
   WPS    Text         Microsoft Works Document
   WRL    Text         Visual Reality Modeling

  
  X back to the top
   X3F    Graphic      Sigma RAW File
   XBM    Graphic      X Bitmap
   XLA    Data         Miscrosoft Excel Macro
   XLC    Data         Miscrosoft Excel Chart
   XLM    Data         Miscrosoft Excel Macro
   XLS    Data         Miscrosoft Excel Spreadsheet
   XLT    Data         Miscrosoft Excel Template
   XLW    Data         Miscrosoft Excel Workbook
   XPM    Graphic      X Pixmap

  
  Y back to the top
   none

  
  Z back to the top
   ZIP    Compression  PKZIP Compression
   ZOO    Compression  ZOO Compression