[Updated] 521 Useful File Extensions List for Developers

.$$$ 

Temporary file

.2gr 

A File That allows Windows to Display Text and Graphics in Standard Mode on a 286 or 386 Computer

.386

Swap File Enables Computer Running in Enhanced mode to Use Windows with Virtual Memory

.3gr

A File That allows Windows to Display Text and Graphics in Enhanced Mode on a 386, 486, or Pentium Computer

.906

Calcomp Plotter

.a3w

Macromedia Authorware Windows 3.5

.abk

Autobackup, Corel Draw

.abr

Brush | Adobe Photoshop

.acl

Keyboard Accelerator, Corel Draw 6

.acm

Windows System Directory File

.acv

Drivers For Compressing or Decompressing Audio Files, OS/2

.ad

After Dark

.adb

1.Appointment DataBase, HP 100LX.

2.Body File Type, Ada Language

.add

Adapter Driver - OS/2

.adm

AfterDark MultiModule

.adr

AfterDark Randomizer. AfterDark is a Screensaver Program That Can be Set to Randomly Display a Variety of Screensaver Patterns one After Another

.ads

Specification File Type, Ada Language

.afm

Adobe Font Metrics - Type 1 Font Metrics

.ag4

Access G4

.ai

Adobe Illustrator

Audio Interchange File Format or AIFF. A Format Developed by Apple Computer For Storing High-Quality Sampled Audio and Musical Instrument Information. It can be Played on PC and Mac

.aiff

Audio Interchange File Format. An Uncompressed Sound Format Developed by Apple Computer for Storing High-Quality Sampled Audio and Musical Instrument Information. It can be Played on PC and Mac, Using QuickTime or Sound Player

.all

Arts and Letters Library

.ani

Animated Cursor

.ans

ANSI Text

.api

Application Program Interface. An Interface Between the Operating System and Application Programs

.app

Macromedia Authorware Package

.arc

ARC Compressed

.arj

A PC Compressed Format Found on European Sites, Which can be Decoded With unArjMac, DeArj, and SITEX10.EXE (win).

.art

An art File, in Some Draw or Paint Applications

.asc

ASCII Text File

.asf

Active Streaming File -Hot Metal Pro

.asm

Assembly Source Code

.asp

Active Server Page - Microsoft

.ast

Assistant File - Claris Works. Assistants Guide The User Through a Task by Asking a Series of Questions and Then Use the Answers to Perform a Task. Assistants in Claris Works can be used to create Such Useful Items as Calendars, Newsletters, Stationery, Labels, and Address Lists, to Make Footnotes Within a File etc.

.att

AT & T

.au

A Sound File Format Used on Sun Microsystems or Other UNIX Computers

.avi

AVI Movie Format

.avs

Intel Video Capture Format

.b64

Base 64, The Encoding Format Used by the Multipurpose Internet Mail Extension

.bak

Backup Copy in DOS or OS/2

.bas

BASIC Program File

.bat

Batch

.bfc

Briefcase Document - Windows 95

.bg

Backgammon Game

.bi

Binary File

.bin

Driver or A MacBinary II Encoded File. This File Type, Downloaded as Macbinary or Binary, can be Decompressed with Stuffit Expander

.bk

Backup Copy

.bk$

Backup File

.blt

Wordperfect For DOS

.bmp

Bitmap

.bnk

Sim City Game File

.brx

Browse Index.Found on Multimedia CD-ROMs

.btm

Batch File - Norton Utilites

.cc

Program File

.cab

Microsoft Compressed Format

.cal

Calendar or CALS

.cap

Caption

.cbt

Computer-Based Training; a Tutorial File

.cch

Corel Chart

.ccm

Lotus cc:Mail

.cda

CD Audio Track

.cdr

CorelDraw

.cdt

Corel Draw Template

.cdx

Corel Draw Compressed File (File Extension)

.cdx

Visual FoxPro Database Index

.cfb

Compton's Multimedia Encyclopedia

.cfg

Configuration

.cfl

Corel Flow

.cgi

Common Gateway Interface. A File That Makes it Possible for HTTP Servers to Interface With Computer Programs to Provide Interactive Functions Like Fill-out Forms

.cgm

CGM Graphics

.chk

Checkdisk - DOS Command

.chp

Chapter - Ventura

.cif

Chapter Information - Venture

.cim

Sim City File

.cit

Intergraph Scanned Image

.clp

Clipboard File

.cmd

Command file - OS/2

.cmf

Corel MetaFile

.cmf

SoundBlaster File

.cmp

LEAD Technologies Graphics

.cmv

Corel Move Animation

.cnf

Configuration File

.cnq

Compuworks Desing Shop

.cob

COBOL Source Code

.com

Command File - Small Version of .EXE

cpe

Fax Cover document

.cpi

Code Page - DOS

.cpl

Control Panel - Windows

.cpp

C++ Program File

.cpr

Knowledge Access graphics

.cpt

Compact Pro

.cpx

Corel Presentation Exchange Compressed File

.crd

Windows Cardfile

.csc

Corel Script

.css

Cascading Style Sheet

.csv

Comma Delimited

.ctl

Control File

.cty

City File - SimCity

.cur

Windows Cursor Image

.cut

Dr. Halo Graphics

.cv

Microsoft CodeView

.cwk

Claris Works

.cws

Claris Works Template

.dat

Data

.db

Table - Paradox

.dbc

Visual Foxpro Database

.dbf

Database File - dBASE

.dbt

Database Text - dBASE

.dbx

DATABEAM Graphics

.dca

IBM Text

.dcs

Color Separation - EPS

.dct

Dictionary

.dd

Disk Doubler

.ddi

Disk Doubler Image

.def

Definition - C++

.der

Certificate

.dev

Device Driver File

.dg

Autotrol Graphics

.dgn

Intergraph Graphics

.dib

DIB Graphics - Windows

.dic

Dictionary

.dif

Data Interchange Format Spreadsheet

.dll

Dynamic Link Library

.doc

Document File

.dot

Document Template - Microsoft Word

.dox

MultiMate Document

.dpi

Dots Per Inch - Graphics

.dpr

Delphi Project File

.drv

Driver

.drw

Desinger Graphics

.ds4

Desinger Graphics, Version 4

.dsf

Desinger Graphics, Version 6

.dwg

AutoCAD Vector Format

.dwg

Drawing - AutoCAD

.dx

Document Imaging

.dxf

AutoCAD Vector Format

.ed5

EDMICS Graphics

.emf

Enhanced Windows Metafile

.eml

Electronic Mail

enc

Encoded

.eps

Encapsulated PostScript Format

.esi

Esri Plot File

.exe

Executable File - Machine code

.fax

Fax

.fdx

Force Index

.fh3

Aldus Freehand 3

.flc

AutoDesk Animation

.fld

Thumbnail Folder - Hijaak

.fli

AutoDesk Animation

.flr

Live3D

.flt

Filter - Graphics Conversion

.fm

Framemaker

.fm3

Format for 1-2-3 Version 3

.fmt

Format - dBASE

.fnt

Font

.fog

Fontographer font

.fon

Bitmapped Font - Windows

.for

FORTRAN

.fot

Windows TrueType Font

.fox

FoxBase

.fp

Claris FileMaker Pro

.fp1

Flying Pigs

.fp3

Filemaker Pro 3

.fpx

FlashPix Bitmap

.frm

Form Desing - Visual Basic

.frs

WordPerfect Graphics Driver

.g4

GTX RasterCAD

.gca

GOCA Graphics

.ged

Arts & Letters Graphics

.gem

GEM Graphics

.geo

VideoScope

.gif

Graphics Interchange Format

.gly

Glossary

.gp3

CCITT Compressed Group 3 TIFF File

.gp4

Group 4 - CALS,ITU.CCITT Compressed Group 4 TIFF File

.gra

Microsoft Graph

.grf

Graph

.grp

Group

.gx1

Show Partner Graphics

.gx2

Show Partner Graphics

.gz

GNU Gzip Compressed File - Unix

.h

Hierarchical Data File

.hdf

Hierarchical Data File

.hed

HighEdit document

.hel

Microsoft Hellbender Game File

.hgl

HP Graphics Language

.hlP

Help

.hpj

Help Project - Visual Basic

.hpl

HP Graphics

.hqx

BinHex (File Name Extension - Macintosh)

.hst

Host

.ht

HyperTerminal

.htm

DOS File Name Extension For a Document With HTML Coding, Which Can be Read by WWW Browsers

.htm

File Name Extension For a Document With HTML Coding, Which Can be Read by WWW Browsers

.hwp

Hangul Word Processor

.hyc

Hyphenation - WordPerfect

.hyp

Hyphenation

.ica

IOCA Graphics

.icb

Targa Bitmap

.icm

Image Colour Matching

.ico

Icon - Windows or OS/2

.icon

Sun Icon and Cursor

.idd

Instrument Definition - MIDI

.ide

Integrated Development Environment Configuration

.idx

Index

.iff

Amiga

.igf

Inset Systems graphics - Hijaak

.iif

Interchange File - QuickBooks for Windows

.il

Icon Library

.ima

Winimage Compressed Format These Files Can be Decoded or Mounted by ShrinkWrap

.image

Mac Disk Image; a Compressed Format Which Can be Decoded or Mounted by DiskCopy, Disk Image Mounter Disk Charmer, and ShrinkWrap (ImageMaster)

.img

.ind

Index

.inf

Information

.ini

Initialization - Configuration Settings

.iob

Imagine File

.isu

Netscape File

.it

MOD Music File Format

.iw

Idlewild Screensaver

.ix

Index File - Framemaker

.jff

JPEG File Interchange Format; a 24-bit Graphic Format. It Can be Opened With QuickTime, a WWW Browser, or a Graphics Viewer Such as JPEGView

.jif

JPEG Image Format

.jpeg

JPEG Bitmap

.jpg

File Extension for JPEG (Joint Photographic Experts Group). A File Stored in JPEG Format. JPEG,an ISO/ITU Standard For Storing Images With High Compression Capability, Uses a Discreet Cosine Transform That can Achieve Compression Rates of 100:1 (singificant Loss of Data From Original) and 20:1 (Minimal Loss). C-Cube Microsystems Introduced The First JPEG Chip

.jt

JT Fax

.jtf

JPEG Bitmap

.kdc

Kodak Photo-Enhancer

.kfx

Kofax

.lbl

Label - dBASE

.lbm

Deluxe Paint Graphics File

.ldb

Lock File - Microsoft Access

.leg

Legacy Document

.lha

File Name Extension for a PC/Amiga Compression Format Decodable by LHA Expander or MacLHA

.lhs

Literate Haskell Source File

.lhz

LHA Compression File

.lib

Library

.lic

License File - Shareware

.log

Log

.lst

List

.lwp

Lotus Word Pro Document

.lzh

LHARC Compression

.lzs

PC/Amiga compression format

.m3d

Motion 3D - Corel

.mac

MacPaint

.maf

Microsoft Access Form

.mak

Makefile

.mam

Microsoft Access Macro

.map

Map - Linkage Editor

.maq

Microsoft Access Query

.mar

Microsoft Access Report

.mat

Microsoft Access Table

.mcs

MathCAD Format

.mcw

Microsoft Word for Macintosh

.mdb

Access Database

.mdx

Multi-Index

.met

Metafile - OS/2

.meu

Menu

.mff

MIDI File Format

.mgf

Micrografx Draw Font

.mi

Miscellaneous

.mic

Microsoft Image Composer

.mid

MIDI File

.miff

An ImageMagick file format

.mil

Group 4 File

.mime

MIME; The Encoding Format used by the Multipurpose Internet Mail Extension

.mme

Mime Encoded File; The Encoding Format Used by the Multipurpose Internet Mail Extension

.mmf

Microsoft Mail File

.mmm

Macromind Animation

.mod

(For Module) - A Music File Format That Contains Digitized Sound Samples A .MOD File Takes More Memory Than a MIDI File Because a MIDI File Contains Instructions for Making Sounds But not The Actual Sound Samples. There are .MOD Players For Amiga, PC, and Macintosh Computers

.mov

Movie - QuickTime

.movie

QuickTime Movie - This File Can be Viewed With QuickTime Player

.moz

Mozilla - Netscape Cache file

.mp2

MPEG Layer II Compressed Audio. This file Can be Played Using QuickTime Player and Some Other Sound Players

.mp3

MPEG Layer III Compressed Audio. This File can be Played With QuickTime Player, Real Player, and Some Other Sound Players

.mpe

MPEG

.mpeg

MPEG Movie or Animation File. This File Can be Played with QuickTime Player

.mpg

MPEG Encoded File. This File is an MPEG Movie, and Can be Played With QuickTime Player

.mpnt

Macintosh MacPaint

.mpp

Microsoft Project project file

.mpt

Microsoft Project Template File

.mpx

Microsoft Project Export File

.mrk

Markup - Informative Graphics

.msg

Message File

.msn

Microsoft Network Document

.msp

Microsoft Paint

.mus

Music

.mvb

Microsoft Multimedia Viewer

.mys

Myst Saved Game File

.ndx

Index - dBASE

.net

Network File

.ng

Norton Guides

.nlm

NLM program - NetWare

.ntf

Notes Template File - Lotus Notes Database

.oab

Outlook Address Book - Microsoft

.oaz

OAZ Fax

.obd

Microsoft Office Binder

.obj

Object module

.ocx

Object Linking and Embedding (OLE) Custom Control

.olb

OLE Object Library

.ole

OLE object

.onx

Onyx Graphics Postershop

.ori

Original

.ovl

Overlay Module

.ovr

Overlay Module

.ozm

Sharp Organizer Memo Bank

.ozp

Sharp Organizer Telephone Bank

.p10

Tektronix Plot10

.pab

Personal Address Book - Microsoft

.pak

Quake Dame Data

.pal

Paintbrush Palette

.pas

Pascal Program File

.pat

Pattern - Corel Draw

.pbk

Microsoft Phonebook

.pbm

Portable Bit Map

.pcd

Photo CD Format

.pcl

HP LaserJet

.pcm

LaserJet cartridge information

.pcs

PICS Animation

.pct

PC Paint

.pcw

PC Write

.pcx

1.PC Paintbrush

2. Graphics file - Zsoft Format

.pdg

PrintShop Deluxev

.pdv

PC Paintbrush Printer Driver

.pfa

Type 1 Font - ASCII

.pfb

Type 1 Font - Encrypted

.pfm

Postscript Font Metrics,Windows Type 1 Font Metrics

.pgm

Portable Gray Map Bitmap

.phtml

HTML Document With Preprocessing Instructions (PPIs)

.pic

PICT Graphics Format, or PIXAR Picture File

.pict

Macintosh QuickDraw/PICT This Kind of File Stores Images in QuickDraw Vector Format. PICT2 Can Have Grayscale Bitmapped Images Also

.pif

Program Information File - Windows

.pit

PackIt - Macintosh Compression

.pix

Inset Systems Graphics

.pjx

Project File - Visual FoxPro

.pkg

AppleLink Package Compression Format These Files are Decodable by StuffIt Expander

.pl

Perl Script

.plt

Plotter Drawing

.pm

Pagemaker

.pm3

Pagemaker 3 Document

.pm4

Pagemaker 4 Document

.pm5

Pagemaker 5 Document

.png

1.Portable Network Graphics Bitmap

2.Paint Shop Pro Browser

.pov

Persistence Of Vision Raytracer

.ppa

PowerPoint Add-in - Microsoft

.ppd

PostScript Printer Description

.ppm

Portable Pixelmap

.pps

PowerPoint Slideshow

.ppt

PowerPoint Presentation

.prd

Printer Driver - Microsoft Word, Word Perfect, Microsoft Works

.prg

A dBASE Source Code File

.prj

Project File

.prn

1.Print File - Temporary

2.Xywrite Printer Driver

3.Post Script File.

.prs

Word Perfect Printer Driver

.prt

Formatted Text

.ps

PostScript. This is a Plain Text File

.psd

Photoshop Document

.pub

Publication - Ventura Publisher,Microsoft Publisher

.pwd

Pocket Word Document - Microsoft

.pwz

Microsoft PowerPoint Wizard

.pxl

Microsoft Pocket Excel

.qbw

QuickBooks for Windows

.qdk

Quarterdeck Qemm

.qlb

Quick Library

.qlc

ATM Font Information

.qry

Microsoft Query

.qt

QuickTime Movie, Binary File Type

.qtm

QuickTime Movie

.r8l

LaserJet Landscape Font

.r8p

LaserJet Portrait Font

.ra

RealAudio

.ram

Real Audio

.ras

Raster Graphics - Sun

.raw

Raw File Format - Bitmap

.rc

A File Name Extension Found in Many UNIX Files (.newsrc, etc.) Which Means "Run Commands"

.rec

Windows Recorder Macro File

.reg

Registration File

.rep

Report File

.rft

RFT-DCA

.rgb

An SGI RGB Image File

.ria

Alpharel Group IV Raster Graphics

.rib

Renderman Graphics

.ric

Roch FaxNet

.rif

Fractal Painter Bitmap

.riff

Resource Interchange File Format A Multimedia File Format; the Microsoft Equivalent to Amiga IFF Format

.rix

RIX Virtual Screen

.rla

Wavefront Raster Image

.rlc

CAD Overlay ESP - Image Systems

.rle

Run Length Encoded

.rm

Real Media

.rmi

RIFF MIDI File

.rnd

AutoShade Format

.rnl

GTX Runlength Raster Graphics

.rpt

Report file

.rtf

Microsoft Text and Graphics

.s

Assembly Language File - Unix

.s3m

MOD Music File

.sam

AmiPro

.sav

Saved Game

.sbp

IBM Storyboard Graphics / Superbase Text

.sc

Source Code - Paradox

.scm

ScreenCam Movie

.scp

Dial-up Networking Script

.scr

1.Screensaver - Windows.

2.Screen Layout - dBASE.

3.Script For Apple's Disk Copy Utility

.sct

Screen Capture Text - Lotus

.sdl

SmartDraw Library

.sea

Self-Extracting Archive (Stuffit or Compact Pro)

.seg

Segment (of a Compressed File Saved in Segments With Stuffit or Compact Pro)

.sep

TIFF Bitmap

.set

Setup Parameters

.sfl

LaserJet Landscape Font

.sfp

LaserJet Portrait Font

.sfs

PCL 5 Scalable Font

.shar

UNIX Shell Archive, Which Can be Decoded by Unshar

.shtml

HTML File With Embedded Server-side Includes (SSIs)

.si

SoftImage Image File

.sig

singature A .sig File Can be Set up and Automatically Attached to Outgoing Email, Newsgroup Postings, etc. It Includes The Name and Contact Information of The Sender, and May also Have ASCII art, Favorite Quotes, etc

.sit

Stuffit Compressed File

.sld

AutoCAD Slide

.slk

Symbolic Link (SYLK) Spreadsheet

.smi

Self-Mounting Image. This file is a Macintosh Disk Image, Similar to an .img File, But it Does Not Require The Use of Disk Copy. When The File is Downloaded, a Disk Image Appears on The Desktop. The Disk Image Will Behave Like a Read-Only Disk

.snd

Sound File

.snm

Netscape Mail

.spd

Speedo Scalable Font

.spx

Screen Peace Extension

.sqb

SyQuest Backup

.src

A File Used in The Creation of .INI Files For Configuration Settings

.sty

Style sheet - Ventura

.svx

Amiga 8SVX Sound

.swp

Swap - Temporary File

.syd

Sysedit Backup File

.syl

SYLK Spreadsheet Format

.synu

SDSC Synu Image

.sys

System File

.tal

Adobe Type Align

.tar

Tar - Tape ARchive. Tar is a UNIX Method of Archiving Files, Which can Also be Used by PCs. Tar Archives Files but Does not Compress Them, so Sometimes .tar Files are Compressed With Other Utilities, Which Produces Extensions like .tar.gz, .tar.Z, and .tgz. Archive Files With The .tar Extension Can be Extracted in UNIX With Tar or on a PC with Winzip or on The Mac With The Program Tar

.tar.gz

Ombined File Name Extension For a File That Has Been Archived Using tar and Then Gzipped

.tar.z

Combined File Name Extension for a File That has Been Archived Using tar and Then Zipped

.taz

Another Way of Writing .tar.Z

.tbk

Asymetrix Toolbook

.tdf

Typeface Definition - Speedov

.tex

Tex or LaTex Document

.tfm

Font Metrics - Intellifont

.tga

TARGA Graphics

.tgz

Another Name For .tar.z and .tar.gz

.theme

Desktop Theme - Windows 95

.thn

Thumbnail

.tif

TIFF Graphics File

.tiff

TIFF Graphics File

.tlb

OLE Type Library

.tmp

Temporary File

.toc

Table Of Contents

.trm

Terminal Settings - Windows

.ttc

TrueType Compressed Font

.ttf

rueType Font

.twf

TabWorks File (File Extension)

.tx8

MS-DOS Text

.txt

ASCII Text File

.usl

LaserJet Landscape Font

.usp

LaserJet Portrait Font

.uu

Uuencode Compressed File

.uue

Uuencode File

.vbp

Visual Basic Project

.vbx

Visual Basic Extension

.vda

Targa Bitmap

.vgr

Ventura

.viff

Khoros Visualization Image File

.vlb

Ventura Library

.voc

Sound Blaster

.vp

Ventura Publisher

.vst

Targa Bitmap

.vue

Relational View - dBASE

.vxd

Virtual Device Driver

.wab

Windows Address Book

.wav

Sound File

.wbk

Microsoft Word Backup

.wdb

Microsoft Works Database

.wid

Ventura Width Table

.win

Windows Backup File

.wiz

Microsoft Word Wizard

.wk1

Lotus 1-2-3, up to 2.01

.wk3

Lotus Version 3

.wk4

Lotus Version 4

.wkq

Quattro Spreadsheet

.wks

1.Lotus Worksheet.

2.Microsoft Works document

.wlr

VRML Page

.wmf

Windows Metafile

.wp

WordPerfect

.wpd

1.Windows Printer Description.

2.WordPerfect Demo.

3.WordPerfect Document

.wpg

WordPerfect Graphics

.wpm

WordPerfect Macro

.wps

Microsoft Works Document

.wpt

WordPerfect Template

.wri

Windows Write Document

.wrk

Symphony Spreadsheet

.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

.wvl

Wavelet Compressed Bitmap

.x

AVS X Image File

.xar

Corel Xara Drawing

.xbm

X Bitmap

.xfx

JetFax

.xif

Xerox Image Format

.xlc

Excel Chart

.xlk

Microsoft Excel Backup

.xlm

Microsoft Excel Macro

.xls

Excel Worksheet

.xlt

Microsoft Excel Template

.xm

MOD Music Format

.xpm

X Pixelmap

.xwd

X Window System Window Dump Image

.xxe

Xxencoded File

.yal

Arts & Letters Click art

.z

Unix compress File

.zip

File Compressed Using PKZIP

.zoo

Zoo