There are thousands of file extensions that allow you to open these different files in different programs, which is way too many to list here. Below you’ll find a list of the most common file extensions that you’ll find.

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z

– A –

ACE – ACE Archiver compression file.

AIF – Audio Interchange File used with SGI and Macintosh applications.

ANI – Animated cursors used in Microsoft Windows.

API – Application Program Interface.

ARC – Compressed file format from an old program called ARC.

ARJ – Compressed file by the ARJ program from Robert Jung.

ART – Clipart.

ASC – ASCII text file.

ASM – Assembler code.

ASP – Microsoft Active Server Page.

AVI – Audio/Video Interleaved used for Windows based movies.

– B –

BAK – Backup Files.

BAS – BASIC programming language sourcecode.

BAT – MS-DOS batch file.

BFC – Briefcase document used in Windows.

BIN – Binary File.

BIN – MacBinary-encoded files.

BMP – Bitmap format.

BUD – Backup Disk for Quicken by Intuit.

BZ2 – Bzip2-compressed files.

– C –

C – C source file.

CAB – Microsoft cabinet file compressed for software (OS) distribution

CAT – Security Catalog file.

CBL – Cobol code.

CBT – Computer Based Training.

CDA – Compact Disc Audio Track.

CDT – Corel Draw Template file.

CFML – ColdFusion Markup Language.

CGI – Common Gateway Interface. Web based programs and scripts.

CHM – Compiled HTML Help files used by Windows.

CLASS – Javascript Class file.

CLP – Windows Clipboard file.

CMD – Dos Command File.

CMF – Corel Metafile.

COM – Command File.

CPL – Control panel item – The settings in Control Panels represent CPL files in the Windows\System folder.

CPP – C++ programming language source code.

CSS – Cascading Style Sheet. Creates a common style reference for a set of web pages.

CSV – Comma Separated Values format.

CTY – CityDesk site from Fog Creek Software.

CWK – ClarisWorks/AppleWorks file.

CWS – AppleWorks template file.

CUR – Cursor in Microsoft Windows.

– D –

DAO – Registry Backup file for Windows registry.

DAT – Data file. Often viewable in a text editor.

DD – Compressed Archive by Macintosh DiskDoubler.

DEB – Debian packages.

DEV – Device Driver.

DIC – Dictionary file.

DIR – Macromedia Director file.

DLL – Dynamic Linked Library. Microsoft application file.

DOC – Document format for Word Perfect and Microsoft Word.

DOT – Microsoft Word Template.

DRV – Device Driver.

DS – TWAIN Data source file.

DUN – Dial-up networking configuration file.

DWG – Autocad drawing.

DXF – Autocad drawing exchange format file.

– E –

EMF – Enhanced Windows Metafile.

EML – Microsoft Outlook e-mail file.

EPS – Encapsulated PostScript supported by most graphics programs.

EPS2 – Adobe PostScript Level II Encapsulated Postscript.

EVE – TTMaker Event Scheduling File.

EXE – DOS based executable file which is also known as a program.

– F –

FFL – Microsoft Fast Find file.

FFO – Microsoft Fast Find file.

FLA – Macromedia Flash movie format.

FNT – Font file.

FSH – EA Sports Game Graphic Editor File

– G –

GIF – Graphics Interchange Format that supports animation. Created by CompuServe and used primarily for web use.

GID – Windows global index. Contains the index information used by “Help” in Windows.

GRP – Microsoft Program Manager Group.

GZ – Unix compressed file.

– H –

HEX – Macintosh binary hex(binhex) file.

HLP – Standard help file.

HT – HyperTerminal files.

HQX – Macintosh binary hex(binhex) file.

HTM – Hyper Text Markup. This markup language is used for web design.

HTML – Hyper Text Markup Language. This markup language is used for web design.

– I –

ICL – Icon Library File.

ICM – Image Color Matching profile.

ICO – Microsoft icon image.

INF – Information file used in Windows.

INI – Initialization file used in Windows.

– J –

JAR – Java Archive. A compressed java file format.

JAVA – File containing Java source code.

JPEG – Compression scheme supported by most graphics programs and used predominantly for web use.

JPG – More common extension for JPEG described above.

JS – JavaScript File – A text file containing JavaScript programming code.

JSP – An HTML page that contains a link to a Java servlet.

– K –

KBM – Keyboard mapping script for Reflection 4.0

KDC – Kodak Photo-Enhancer image

KIZ – Kodak digital postcard

KQP – Konica camera file

– L –

LAB – Microsoft Excel mailing labels.

LG – OOTP Developments saved games.

LGO – Windows 9x startup logo.

LHZ – Compressed archive by the LHA program from Haruyasu Yoshizaki.

LIT – eBooks in Microsoft Reader format.

LNK – Windows 9x shortcut file.

LOG – Application log file.

LSP – Autocad(visual) lisp program.

– M –

MAQ – Microsoft Access Query.

MAR – Microsoft Access Report.

MDB – Microsoft Access DataBase File.

MDL – Rose model file. Opens with Visual Modeler or Rational Rose.

MFM – MFWorks map file standard by Keigan Systems.

MHT – Microsoft single file web archive.

MID – MIDI music file.

MOD – Microsoft Windows 9.x kernel module.

MOV – Quicktime movie.

MP3 – MPEG Audio Layer 3.

MPEG – Animation file format.

MPP – Microsoft Project File.

MSG – Microsoft Outlook message file.

MSG – Fidonet messages.

– N –

NCF – Netware command File.

NDX – ArcView Fonts Index File by ESRI

NFF – Haines Neutral File Format

NFF – WorldToolKit Neutral File Format

NITF – National Imagery Transmission Format

NLM – Netware loadable Module.

– O –

O – Object file, used by linkers.

OBD – Microsoft Office Binder file. Ties Office docs together without having to load separate programs

OCX – ActiveX Control: A component of the Windows environment.

OFT – Microsoft Outlook template

OGG – Ogg Vorbis digitally encoded music file.

OST – Microsoft Exchange/Outlook offline file.

– P –

PAK – WAD file that contains information about levels, settings, maps, etc for Quake and Doom.

PCL – Printer Control Language file. PCL is a Page Description Language developed by HP.

PCT – Macintosh drawing format.

PDF – Portable Document File by Adobe. Viewable in a web browser or with Adobe Acrobat.

PDF – Printer Description File. Provides printer support for certain applications.

PDR – Port driver for windows 95. It is actually a virtual device driver (vxd).

PHP – Web page that contains a PHP script.

PHTML – Web page that contains a PHP script.

PIF – Program Information File

PIF – Vector graphics GDF file(IBM Mainframe)

PIF – Macintosh Compressed archive

PL – Perl source code file.

PM – Perl Module.

PM3 – PageMaker 3.0 document.

PM4 – PageMaker 4.0 document.

PM5 – PageMaker 5.0 document.

PM6 – PageMaker 6.0 document.

PNG – Portable Network Graphic file.

POL – System Policy file for Windows NT.

POT – Microsoft PowerPoint design template.

PPD – PostScript Printer description file used in Macintosh and Windows operating systems to provide printer specific features to a driver.

PPK – PuTTY Private Key.

PPS – Microsoft PowerPoint slide show.

PPT – Microsoft PowerPoint presentation(default extension).

PRN – A print file created as the result of “printing to file”.

PS – PostScript file.

PSD – Native Adobe Photoshop format.

PSP – Paint Shop Pro image.

PST – Personal Folder File for Microsoft Outlook.

PUB – Microsoft Publisher document.

PWL – Windows Password list file.

– Q –

QBB – QuickBooks backup company file.

QBW – QuickBooks working company file

QIF – Quicken Import file.

QXD – Quark Express file.

– R –

RAM – RealAudio Metafile.

RAR – RAR compressed archive created by Eugene Roshall.

RAW – Raw File Format.

RDO – Raster Document Object. Proprietary file type used on Xerox Digipath Scan and Makeready workstations.

REG – Registry file that contains registry settings.

RM – RealAudio video file.

RPM – RedHat Package Manager.

RSC – Standard resource file.

RTF – Rich Text Format.

– S –

SCR – Screen Saver file.

SEA – Self-extracting archive for Macintosh Stuffit files.

SGML – Standard Generalized Markup Language.

SH – Unix shell script.

SHTML – HTML file that supports Server Side Includes(SSI).

SIT – Compressed Macintosh Stuffit files.

SMD – SEGA mega drive ROM file.

SVG – Adobe scalable vector graphics file.

SWF – Shockwave Flash file by Macromedia.

SWP – DOS swap file.

SYS – Windows system file used for hardware configuration or drivers.

– T –

TAR – Unix Tape Archive.

TCW – TurboCAD Drawing File.

TGA – Targa bitmap.

TIFF – Tagged Image File Format. Universal graphics format supported by most graphics applications.

TMP – Windows temporary file.

TTF – True Type font.

TXT – Text Format.

– U –

UDF – Uniqueness Definition File. Used for Windows unattended installations.

UUE – UU-encoded file.

– V –

VBS – Microsoft Visual Basic script file.

VBX – Microsoft Visual Basic extension.

VM – Virtual Memory file.

VXD – Windows 9x virtual device driver.

– W –

WAV – Waveform sound file.

WMF – Windows Metafile (graphics format).

WRI – Write Document: This is equivalent to RTF, Rich Text Format, that enables saving text with formatting information.

WSZ – Winamp Skin.

– X –

XCF – The GIMP’s native image format.

XIF – Wang imaging file. Wang Image Viewer comes with Windows 95/2000.

XIF – Xerox Image file (same as TIFF).

XIF – Image file eXtended by ScanSoft is similar to TIFF and is a Pagis application format.

XLS – Microsoft Excel Spreadsheet.

XLT – Microsoft Excel Template.

XML – Extensible markup language.

XSL – XML style sheet.

– Y –

YBK – Microsoft Encarta yearbook file

– Z –

ZIP – Compressed Zip archive.

If there is an extension that you want to know about that isn’t listed here then Fileinfo.com will probably list it, so try searching on there.

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