File Extensions File Extensions for common file types. Knowing the extension of a file can help you open it.

File Extensions

File extensions are often used to determine the program that created the file. While users can rename files and/or associate odd extensions with particular programs, the following are some fairly standard associations.

Please let me know if you have applications not listed here, please advise so I can add them to the list. 

You can click on the first letter of the extension to go to that group
$ _ 0 1 2 3 4 5 6 7 8 9 ? ~


.A UNIX Library or ADA Program
.A01 ARJ Multi-volume Compressed Archive (can be 01 to 99)
.A11 Graphic
.A3K Yamaha A3000 Sampler File
.A3M Unpackaged Authorware MacIntosh File
.A3W Unpackaged Authorware Windows File
.A4M Unpackaged Authorware MacIntosh File
.A4P Authorware File without runtime)
.A4W Unpackaged Authorware Windows File
.A5W Unpackaged Authorware Windows File
.A86 A86 Assembler Program File
.A_T A-Train
.AAM Authorware Shocked File
.AAS Authorware Shocked Packet
.AB6 AB Stat Data
.AB8 AB Stat Data
.ABC Flowchart
.ABD AmBiz Bonus Calculator Data File
.ABF Adobe Binary Screen Font
.ABK Corel Draw AutoBackup or Any Automatic Backup
.ABR Photoshop Brush
.ABS Abstracts
.ACA MS Agent Character File
.ACD Chromeleon Channel Raw Data or Sonic Foundry Acid Music File
.ACE The Ace Archiver Compressed File
.ACF MS Agent Character File
.ACG MS Agent Preview File
.ACL Corel Draw 6 Keyboard Accelerator
.ACM Audio Compression Manager Driver or Windows System File
.ACO Photoshop Color Swatch File
.ACP MS Office Assistant Preview File
.ACR American College of Radiology File
.ACS MS Agent Character File
.ACT MS Office Actor Program File or FoxPro Action Diagram
.ACV OS/2 Audio Drivers
.AD AfterDark Screen Saver
.ADA ADA Program File
.ADB Ada Package Body or HP Organizer Appointment Database
.ADC Chromeleon Demo Data File
.ADD Adapter Device Driver
.ADE MS Access Project Extension
.ADF Adapter Description File or Admin Config File or
Amiga Disk File
.ADI AutoCAD Plotter File
.ADL MCA Adapter Description Library
.ADM After Dark Screen Saver Module
.ADN Add In Utility or MS Access Blank Project Template
.ADP FaxWorks Modem Setup File or Astound Dynamite File or MS Access Project
.ADR After Dark Random Screen Saver Module
.ADS ADA Package Specification
.ADX Approach Index File
.AF2 ABC Flowchart
.AF3 ABC Flowchart
.AFL Lotus Font
.AFM Outline Font Metric
.AFP Flowchart Symbol Palette
.AFS Filter Factory Photoshop Filter
.AFT Flowchart Template
.AFW Flowchart Work Area
.AG4 Access G4 File
.AI Illustrator Vector Graphic
.AIF Knowledgeware Setup Information or Audio Interchange File
.AIM AOL Instant Messenger File
.AIO APL File Transfer Format
.AIR Align It! Resource File
.AIS Array of Intensity Samples (Graphic) or
Velvet Studio Instruments or ACDSee Image Sequence File
.AKF Acrobat Key File
.AKW RoboHELP Help Project Index File
.ALB JASC Image Commander Album
.ALL Arts & Letters Symbols and Characters or WP Printer Info
.ALT WP Menu File
.AMS Extreme's Tracker Module Format or Velvet Studio Module
.ANC Canon Computer Pattern Maker File
.ANI Animated Cursor
.ANL Project Analyzer Saved Analysis
.ANM Animation
.ANN Help Annotation
.ANS ANSI Graphic or MS Word Text and Layout
.ANT SimAnt for Windows Saved Game File
.APC Lotus Printer Driver Characters or Centura Team Developer Compiled
Application File
.APD Lotus Printer Driver or Centura Team Developer Dynamic
Application Library File
.APF Lotus Printer Driver Fonts or Acrobat Profile File
.API Lotus Printer Driver Info or Application Program Interface
.APL Centura Team Developer Application Library File
.APP R:Base, Symphony, DR-DOS, FoxPro (or other) Application or
Centura Team Developer Normal Mode Application File
.APR Lotus Approach 97 File
.APS MS Visual C++ File
.APT Centura Team Developer Text Mode Application File
.ARC Archive File or Compressed File
.ARI Aristotle Audio File
.ARJ Compressed Archive
.ART Clip Art File or Xara Studio Drawing or
Canon Crayola Art File or Another Ray Tracer Format or
AOL Johnson-Grace Compressed File
.ASA MS Visual InterDev File or Active Server Document
.ASC ASCII Text File or PGP Armored Encrypted File
.ASD MS Word Automatic Backup or Lotus Screen Driver or
MS Advanced Streaming Format Description File
.ASE Velvet Studio Sample
.ASF MS Active Streaming File or Statgraphics Data or
Lotus Screen Font or APL*Plus/PC APL Shared File
.ASH Assembler Header
.ASI Assembler Include
.ASK askSam Data
.ASM Assembler Source Language
.ASO Assembler Object or Astound Dynamite Objects
.ASP Active Server Page or Procomm Plus ASPECT Program or
Astound Presentation File
.ASR Automap Route
.AST Astound Multimedia File or Claris Works Assistant File
.ASV DataCAD Autosave File
.ASX Active Streaming File or Cheyenne Backup Script or
MS Advanced Streaming Redirector File or Video File
.ATT AT&T Group 4 Bitmap (fax)
.AU Music File (various)
.AVB Inculan Anti-Virus Virus Infected File
.AVI Audio Video Interleave File
.AVR Audio Visual Research Sound File
.AVS Animation File or Application Visualization System Format
.AWD Faxviewer Document
.AXR Telsis Digital Audio File