List of Extensions

A

ABK Corel Draw AutoBackup
ACL Corel Draw 6 keyboard accelerator
ACM Used by Windows in the system directory
ACP Microsoft Office Assistant Preview file
ACT Microsoft Office Assistant Actor file
ACV OS/2 drivers that compress and decompress audio data
AD After Dark screensaver
ADB Appointment database used by HP 100LX organizer
ADD OS/2 adapter drivers used in the boot process
ADM After Dark MultiModule screensaver
ADP Used by FaxWorks to do setup for fax modem interaction
ADR After Dark Randomizer screensaver
AFM Adobe font metrics
AF2 ABC Flowchart file
AF3 ABC Flowchart file
AI Adobe Illustrator drawing
AIF Apple Mac AIFF sound
ALB JASC Image Commander album
ALL Arts & Letters Library
AMS Velvert Studio music module (MOD) file
ANC Canon Computer Pattern Maker file that is a selectable list of pattern colors
ANI Animated Cursor
ANS ANSI text
API Application Program Interface file; used by Adobe Acrobat
APR Lotus Approach 97 file
APS Microsoft Visual C++ file
ARC LH ARC (old version) compressed archive
ARJ Robert Jung ARJ compressed archive
ART Xara Studio drawing
ART Canon Crayola art file
ASA Microsoft Visual InterDev file
ASC ASCII text
ASD WinWord AutoSave
ASM Assembler language source file
ASP Active Server Page (an HTML file containing a Microsoft server-processed script)
ASP Procomm Plus setup and connection script
AST Claris Works "assistant" file
ATT AT&T Group 4 bitmap
AVI Microsoft Video for Windows movie
AWD FaxView document

B

BAK Backup file
BAS BASIC code
BAT Batch file
BFC Windows 95 Briefcase document
BG Backgammon for Windows game
BI Binary file
BIF GroupWise initialization file
BIN Binary file
BK Sometimes used to denote backup versions
BK$ Also sometimes used to denote backup versions
BKS An IBM BookManager Read bookshelf
BMK An A bookmark file
BMP Windows or OS/2 bitmap
BM1 Apogee BioMenace data file
BRX A file for browsing an index of multimedia options
BSP Quake map
BS1 Apogee Blake Stone data file
BTM Batch file used by Norton Utilities
B4 Helix Nuts and Bolts file

C

C C code
CAB Microsoft cabinet file (program files compressed for software distribution)
CAL CALS Compressed Bitmap
CAL Calendar schedule data
CAS Comma-delimited ASCII file
CAT IntelliCharge categorization file used by Quicken
CB Microsoft clean boot file
CCB Visual Basic Animated Button configuration
CCF Multimedia Viewer configuration file used in OS/2
CCH Corel Chart
CCM Lotus CC:Mail "box" (for example, INBOX.CCM)
CDA CD Audio Track
CDF Microsoft Channel Definition Format file
CDI Phillips Compact Disk Interactive format
CDR Core Draw drawing
CDT Corel Draw template
CDX Corel Draw compressed drawing
CEL CIMFast Event Language file
CFB Comptons Multimedia file
CFG Configuration file
CGI Common Gateway Interface script file
CGM Computer Graphics Metafile
CH OS/2 configuration file
CHK File fragments saved by Windows Disk Defragmenter or ScanDisk
CHP Ventura Publisher chapter
CIL Clip Gallery download package
CIM Sim City 200 file
CIN OS/2 change control file that tracks changes to an INI file
CK1 iD/Apogee Commander Keen 1 data file
CK2 iD/Apogee Commander Keen 2 data file
CK3 iD/Apogee Commander Keen 3 data file
CK4 iD/Apogee Commander Keen 4 data file
CK5 iD/Apogee Commander Keen 5 data file
CK6 iD/Apogee Commander Keen 6 data file
CLASS Java class
CLP Windows Clipboard file
CLS Visual Basic Class Module
CMD Command file for Windows NT (similar to a DOS .BAT file)
CMD DOS CP/M command file
CMD dBase-II program file
CMF Corel Metafile
CMP JPEG Bitmap
CMP Address document
CMV Corel Move animation
CMX Corel Presentation Exchange image
CNF Configuration file used by Telnet, Windows, and other applications
CNM Windows application menu options and setup file
CNQ Compuworks Design Shop file
CNT Windows (or other) system content files for the help index and other purposes
COB trueSpace2 object
COD Microsoft C compiler output as displayable assembler with original C as comments
COM Command file (program)
CPD Fax Cover document
CPE Fax Cover document
CPI Microsoft MS-DOS code page information file
CPL Control Panel extension
CPL Corel colour palette
CPP C++ code
CPR Corel Presents Presentation
CPT Corel Photo-Paint image
CPX Corel Presentation Exchange Compressed drawing
CRD Cardfile file
CRP Corel Presents Run-Time Presentation
CRT Certificate file
CSC Corel Script
CSP PC Emcee On-Screen image
CSV Comma-separated values file
CT Scitex CT Bitmap
CTL Used in general to mean a file containing control information.
CUE Microsoft Cue Cards data
CUR Windows Cursor
CUT Dr Halo bitmap
CV Corel Versions archive
CV Microsoft CodeView information screen
CWK Claris Works data file
CWS Claris Works template
CXX C++ source code file

D

DAT Data file
DAT WordPerfect Merge Data
DBF Aston-Tate dBASE database
DBX DataBeam image
DCR Shockwave file
DCS Desktop Color Separation file
DCX Fax image (based on PCX)
DDF BTRIEVE database
DEF SmartWare II data file
DEF C++ Definition
DER Certificate file
DIB Device-Independent Bitmap
DIC Dictionary
DIF Data Interchange Format spreadsheet
DIR Macromedia Director file
DIZ Description file
DLG C++ Dialogue Script
DLL Dynamic-Link Library
DMF X-Trakker music module (MOD) file
DOC FrameMaker or FrameBuilder document
DOC WordStar document
DOC WordPerfect document
DOC Microsoft Word document
DOT Microsoft Word document Template
DPR Borland Delphi project header file
DRV Driver
DRW Micrografx Designer/Draw
DSG DooM saved game
DSM Dynamic Studio music module (MOD) file
DSP Microsoft Developer Studio project
DSQ Corel QUERY file
DSW Microsoft Developer Studio workspace
DWG AutoCAD drawing eXchange format
DXF AutoDesk Drawing Interchange format

E

EMF Enhanced Windows Metafile
ENC Encore file
EPS Encapsulated PostScript image
ER1 ERWin file
ERX ERWin file
EVY Envoy document
EWL Microsoft Encarta document
EXE Executable file (program)

F

F FORTRAN file
F77 FORTRAN file
F90 FORTRAN file
FAR Farandole Composer music module (MOD) file
FAV Microsoft Outlook navigation bar
FAX FAX Type image
FH3 Aldus Freehand 3 drawing
FIF Fractal image file
FITS CCD camera image
FLC AutoDesk FLIC animation
FLI AutoDesk FLIC animation
FLT Corel filter
FLT StarTrekker music module (MOD) file
FMB Oracle binary source code for form, version 4.0 and later
FMT Oracle text format of form, version 4.0 and later
FMT Microsoft Schedule+ print file
FMX Oracle executable form, version 4.0 and later
FOG Fontographer font
FON System font
FOR FORTRAN file
FOT Font-related file
FP FileMaker Pro file
FP1 Flying Pigs for Windows data file
FP3 FileMaker Pro file
FPX FlashPix bitmap
FRM Form
FRM FrameMaker or FrameBuilder document
FRM Oracle executable form version 3.0 and earlier
FRM Visual Basic form
FRM WordPerfect Merge form
FRX Visual Basic form stash file

G


GAL Corel Multimedia Manager album
GCP Ground Control Point file used in image processing of remote sensing data .
GED Graphic Environment Document (drawing)
GEM GEM metafile
GEN Ventura-Generated text file
GFC Patton&Patton Flowcharting 4 flowchart file
GFI Genigraphics Graphics Link presentation
GFX Genigraphics Graphics Link presentation
GID Windows 95 global index file (containing help status)
GIF CompuServe bitmap
GIM Genigraphics Graphics Link presentation
GIX Genigraphics Graphics Link presentation
GNA Genigraphics Graphics Link presentation
GNX Genigraphics Graphics Link presentation
GRA Microsoft Graph
GRD Grid file, used in image processing of remote sensing data often to form map projections.  GRP Program Manager Group
GTK Graoumftracker (old) music module (MOD) file
GT2 Graoumftracker (new) music module (MOD) file
GWX Genigraphics Graphics Link presentation
GWZ Genigraphics Graphics Link presentation
GZ Unix Gzip compressed file

H

H C program header
HED HighEdit document
HEL Microsoft Hellbender saved game
HEX Macintosh BinHex 2.0 file
HGL HP Graphics Language drawing
HLP Help file
HOG Lucas Arts Dark Forces WAD file
HPJ Visual Basic Help Project
HPP C++ program header
HQX Macintosh BinHex 4.0 file
HST History file
HT HyperTerminal
HTM Hypertext document
HTML Hypertext document
HTX Extended HTML template

I

ICA Citrix file
ICB Targa bitmap
ICM Image Color Matching profile file
ICO Windows Icon
IDD MIDI Instrument Definition
IDQ Internet Data Query file
IFF Amiga ILBM
IGF Inset Systems metafile
IIF QuickBooks for Windows interchange file
IMA WinImage file
IMG GEM image
INC Assembler language or Active Server include file
INF Information file
INI Initialization file
INP Oracle source code for form, version 3.0 and earlier
INS InstallShield install script
INS X-Internet sign-up file
ISO Lists the files on a CD-ROM; based on the ISO 9660 CD-ROM file system standard
ISP X-Internet sign-up file
ISU InstallShield uninstall script
IT Impulse Tracker music module (MOD) file
IW Idlewild screensaver

J

JAR Java ARchive file (a compressed file for applets and related files)
JAVA Java source code
JBF Paint Shop Pro image browser file
JFF JPEG bitmap
JIF JPEG bitmap
JMP SAS JMPDiscovery chart-to-statistics file
JN1 Epic MegaGames Jill of the Jungle data file
JPEG JPEG bitmap
JPG JPEG bitmap
JS JavaScript source code
JTF JPEG bitmap

K

KDC Kodak Photo-Enhancer
KFX KoFax Group 4 image
KYE Kye game data

L

LBM Deluxe Paint bitmap
LDB Microsoft Access lock file
LEG Legacy document
LHA Alternate file suffix for LZH
LIB Library
LIS Output file produced by a Structured Query Reporting (SQR) program
LOG 1. Log file
LOG 2. Log file used by pokerstars for errors in their poker software
LPD Helix Nuts and Bolts file
LRC Intel Video Phone file
LST List file
LWO Lightwave Object file
LWP Lotus Wordpro 96/97 file
LZH LH ARC compressed archive
LZS Skyroads data file

M

MAD Microsoft Access module
MAF Microsoft Access Form
MAK Visual Basic or MS Visual C++ Project
MAM Microsoft Access Macro
MAP Map file
MAP Duke Nukem 3D WAD game file
MAQ Microsoft Access Query
MAR Microsoft Access Report
MAS Lotus Freelance Graphics Smartmaster file
MAT Microsoft Access Table
MAX Paperport file
MAZ Hover maze data
MB1 Apogee Monster Bash data file
MCC Dialer10 calling card
MCS MathCAD image
MCW Microsoft Word for Macintosh document
MDA Microsoft Access add-in
MDB Microsoft Access database
MDE Microsoft Access MDE file
MDL Digital Tracker music module (MOD) file
MDL Quake model file
MDN Microsoft Access blank database template
MDW Microsoft Access Workgroup
MDZ Microsoft Access wizard template
MED Music Editor, OctaMED music module (MOD) file
MER Format for interchanging spreadsheet/database data; recognized by Filemaker, Excel, and others
MET Presentation Manager metafile
MI Miscellaneous
MIC Microsoft Image Composer file
MID MIDI music
MMF Microsoft Mail File
MMM Microsoft Multimedia Movie
MOD FastTracker, StarTrekker, Noise Tracker (etc.) music module file
MOD Microsoft Multiplan spreadsheet
MOV QuickTime for Windows movie
MPE MPEG animation
MPEG MPEG animation
MPG MPEG animation
MPP Microsoft Project file
MPP CAD drawing file format
MP3 MPEG Audio Layer 3 (AC3) file
MSG Microsoft Mail message
MSN Microsoft Network document
MSP Microsoft Paint bitmap
MTM MultiTracker music module (MOD) file
MUS Music
MVB Microsoft Multimedia Viewer file
MWP Lotus Wordpro 97 Smartmaster file

N

NAP NAP Metafile
NCB Microsoft Developer Studio file
NSF Lotus Notes database
NST Noise Tracker music module (MOD) file
NTF Lotus Notes database template

O


OBD Microsoft Office binder template
OBD Microsoft Office Binder
OBJ Object file
OBZ Microsoft Office Binder Wizard
OCX Microsoft Object Linking and Embedding custom control
OFN Microsoft Office FileNew file
OFT Microsoft Outlook template
OKT Oktalyzer music module (MOD) file
OLB OLE Object Library
OLE OLE object
OPT Microsoft Developer Studio file
ORG Lotus Organiser file
OR2 Lotus Organiser 2 file
OR3 Lotus Organiser 97 file


P


P10 Tektronix Plot 10 drawing
PAB Microsoft Personal Address Book
PAK Quake WAD file
PAL Windows colour palette
PAT Corel Draw pattern
PBK Microsoft Phonebook
PBM Portable Bitmap
PCD Kodak Photo-CD image
PCL HP Laserjet bitmap
PCS PICS animation
PCT Macintosh PICT drawing
PCX ZSoft PC Paintbrush bitmap
PDF Adobe Acrobat Portable Document Format or Netware Printer Definition File
PDF Package Definition File from Microsoft Systems Management Server
PDQ Patton&Patton Flowcharting PDQ Lite file
PFA Type 1 font (ASCII)
PFB Type 1 font (binary)
PFC PF Component
PFM Printer Font Metrics
PGL HP Plotter drawing
PGM Portable Graymap (bitmap)
PIC PC Paint bitmap
PIC Lotus picture
PIC Macintosh PICT drawing
PIF Program Information File
PIF IBM PIF drawing
PIG Lucas Arts Dark Forces WAD file
PIN Epic Pinball data file
PIN Epic Pinball data file
PIX Inset Systems bitmap
PJ MKS Source Integrity file
PKG Microsoft Developer Studio application extension (similar to a DLL file)
PL Perl program
PLT HPGL Plotter drawing
PLT AutoCAD Plot drawing
PM5 Pagemaker 5.0 file
PM6 Pagemaker 6.0 file
P65 Pagemaker 6.5 file
PNG Portable Network Graphics bitmap
PNG Paint Shop Pro Browser catalogue
PNT MacPaint graphic file
POT Microsoft PowerPoint Template
PP4 Picture Publisher 4 bitmap
PPA Microsoft PowerPoint Add-in
PPM Portable Pixelmap bitmap
PPS Microsoft PowerPoint slide show
PPT Microsoft PowerPoint presentation
PRE Lotus Freelance presentation
PRF Windows system file
PRN Print Table (space delimited text)
PRS Harvard Graphics for Windows presentation
PRZ Lotus Freelance Graphics 97 file
PS Postscript Interpreted drawing
PSD Adobe Photoshop bitmap
PST Microsoft Outlook Personal Folder File
PTM Polytracker music module (MOD) file
PUB Ventura Publisher publication
PUB Microsoft Publisher document
PWD Microsoft Pocket Word document
PWZ Microsoft PowerPoint Wizard
PXL Microsoft Pocket Excel spreadsheet

Q

QAD PF QuickArt Document
QBW QuickBooks for Windows file
QDT Quick Books data file from the Quicken UK Accountancy/Tax/Invoice program
QLB Quick Library
QRY Microsoft Query
QT QuickTime Movie
QTM QuickTime Movie
QXD Quark XPress file

R

R Pegasus Mail resource file
RA Real Audio sound
RAM Real Audio sound
RAS Sun Raster Images bitmap
RAW Raw File Format (bitmap)
RC Microsoft Visual C++ Resource Script
REC Recorder macro
REG Registration file
RES Microsoft Visual C++ Resource
RFT RFT-DCA
RLE Run-Length Encoded bitmap
RM Real Audio video file
RMI MIDI music
ROV Rescue Rover data file
RPT Microsoft Visual Basic Crystal Reports file
RTF Rich Text Format document
RTM Real Tracker music module (MOD) file

S

SAM Ami Professional document
SAV Saved game file
SCC Microsoft Source Safe file
SCD Matrix/Imapro SCODL slide image
SCD Microsoft Schedule+ 7
SCH Microsoft Schedule+ 1
SCN trueSpace2 scene
SCP Dial-Up Networking Script
SCR Windows screensaver
SCR Fax image
SCT Scitex CT bitmap
SC2 Microsoft Schedule+ 7
SDL SmartDraw library
SDR SmartDraw drawing
SDT SmartDraw template
SEA Self-expanding archive (used by Stuffit for Mac files and possibly by others)
SEP Tagged Image File Format (TIFF) bitmap
SHB Corel Show presentation
SHB Document shortcut file
SHG Hotspot bitmap
SHS Shell scrap file
SHW Corel Show presentation
SIT Stuffit archive of Mac files
SLK Symbolic Link (SYLK) spreadsheet
SND NeXT sound
SND Mac Sound Resource
SQC Structured Query Language (SQR) common code file
SQR Structured Query Language (SQR) program file
STM Scream Tracker music module (MOD) file
STY Ventura Publisher style sheet
SVX Amiga 8SVX sound
SYS System file
S3M Scream Tracker 3 music module (MOD) file

T

TAR Tape Archive
 TAZ Unix Gzip/Tape Archive
TEX Texture file
TGA Targa bitmap
TGZ Unix Gzip/Tape Archive
THEME Windows 95 Desktop Theme
THN Graphics Workshop for Windows thumbnail
TIF Tag Image File Format (TIFF) bitmap
TIFF Tag Image File Format (TIFF) bitmap
TIG Tiger file, used by US government to distribute maps
TLB OLE Type Library
TMP Windows temporary file
TRM Terminal file
TRN MKS Source Integrity project usage log
TTF TrueType font
TWF TabWorks file
TWW Tagwrite Template
TX8 MS-DOS Text
TXT Text
T2T Sonata CAD modelling software file

U

UDF Windows NT Uniqueness Database File
ULT Ultratracker music module (MOD) file
URL Internet shortcut
USE MKS Source Integrity file


V

VBP Visual Basic Project
VBW Microsoft Visual Basic workspace
VBX Visual Basic custom control
VCF Vevi Configuration File; defines objects for use with Sense8's WorldToolKit
VDA Targa bitmap
VI Virtual Instrument file from National Instruments LABView product
VLB Corel Ventura Library
VOC Creative Labs Sound Blaster sound
VP Ventura Publisher publication
VSD Visio drawing (flow chart or schematic)
VST Targa bitmap
VSW Visio Workspace file
VXD Microsoft Windows virtual device driver



W

WAD Large file for Doom game containing video, player level, and other information
WAV Windows Waveform sound
WB1 QuattroPro for Windows spreadsheet
WB2 QuattroPro for Windows spreadsheet
WBK Microsoft Word Backup
WBL Argo WebLoad II upload file
WCM WordPerfect Macro
WDB Microsoft Works database
WEB CorelXara Web document
WGP Wild Board Games data file
WID Ventura width table
WIL WinImage file
WIZ Microsoft Word Wizard
WK1 Lotus 123 versions 1 & 2 spreadsheet
WK3 Lotus 123 version 3 spreadsheet
WK4 Lotus 123 version 4 spreadsheet
WKS Lotus 123 Worksheet spreadsheet
WKS Microsoft Works document
WLF Argo WebLoad I upload file
WLL Microsoft Word Add-In
WMF Windows Metafile
WOW Grave Composer music module (MOD) file
WP WordPerfect document
WPW Novel PerfectWorks document
WP4 WordPerfect 4 document
WP5 WordPerfect 5 document
WP6 WordPerfect 6 document
WPD WordPerfect Demo
WPD WordPerfect Document
WPG WordPerfect Graphic
WPS Microsoft Works document
WPT WordPerfect Template
WQ1 QuattroPro/DOS spreadsheet
WQ2 QuattroPro/DOS version 5 spreadsheet
WRI Write document
WRL Virtual Reality model
WS1 WordStar for Windows 1 document
WS2 WordStar for Windows 2 document
WS3 WordStar for Windows 3 document
WS4 WordStar for Windows 4 document
WS5 WordStar for Windows 5 document
WS6 WordStar for Windows 6 document
WS7 WordStar for Windows 7 document
WSD WordStar 2000 document
WVL Wavelet Compressed Bitmap


X


XAR Corel Xara drawing
XLA Microsoft Excel add-in
XLB Microsoft Excel toolbar
XLC Microsoft Excel chart
XLD Microsoft Excel dialogue
XLK Microsoft Excel backup
XLM Microsoft Excel macro
XLS Microsoft Excel worksheet
XLT Microsoft Excel template
XLV Microsoft Excel VBA module
XLW Microsoft Excel workbook / workspace
XM FastTracker 2, Digital Tracker music module (MOD) file
XR1 Epic MegaGames Xargon data file
XTP XTree data file
XY3 XYWrite III document
XY4 XYWrite IV document
XYP XYWrite III Plus document
XYW XYWrite for Windows 4.0 document

Y

YAL Arts & Letters clipart library
YBK Microsoft Encarta Yearbook


Z

Z Unix Gzip
ZIP Zip file
ZOO An early compressed file format


Numbers and Symbols


000-999 Used to number old versions of files and number related data files
12M Lotus 123 97 Smartmaster file
123 Lotus 123 97 file
2GR and 3GR VGA Graphics driver/configuration files under Windows
386 A file for use in an 80386 or higher microprocessor
669 Composer 669, Unis Composer music mod file
#01 and higher A method of numbering picture files for a roll of film that has been scanned  $$$ Used by OS/2 to keep track of archived files @@@ Screen files used in the installation and instruction on use of applications

Source - Tips & Tricks