| Extension |
File Type |
File Description |
| .a | Developer | Static Library |
| .a2m | Audio | AdLib Tracker 2 File (Most common) |
| .a2m | Audio | AdLib Tracker 2 File (Most common) |
| .a2w | Developer | Alice World |
| .a3l | Data | Authorware 3 Library |
| .a3m | Data | Authorware 3 Macintosh File |
| .a3w | Data | Authorware 3 Windows File |
| .a4l | Data | Authorware 4 Library |
| .a4m | Data | Authorware 4 Macintosh File |
| .a4w | Data | Authorware 4 Windows File |
| .a5l | Data | Authorware 5 Library |
| .a5w | Data | Authorware 5 Windows File |
| .a65 | Data | Authorware 6.5 File |
| .a6p | Executable | Authorware 6 Program |
| .aa | Audio | Audible Audio Book File (Most common) |
| .aa3 | Audio | ATRAC Audio File |
| .aac | Audio | Advanced Audio Coding File |
| .aawdef | Misc | Ad-Aware Definitions File |
| .aax | Audio | Audible Enhanced Audiobook File |
| .ab | Developer | Applix Builder File (Most common) |
| .ab1 | Data | DNA Electropherogram File |
| .ab3 | Data | PhotoImpact 3 Album File |
| .abbu | Backup | Address Book Backup |
| .abc | Audio | ABC Music Notation (Most common) |
| .abc | Audio | ABC Music Notation (Most common) |
| .abcd | Data | AudioVisual Book Data File |
| .abf | Font | Adobe Binary Screen Font File |
| .abi | Data | DNA Chromatogram File |
| .abk | Backup | Automatic Backup (Most common) |
| .abm | Raster Image | Photo Album (Most common) |
| .abp | Data | AVS Barcode Profile |
| .abr | Misc | Adobe Photoshop Brushes File |
| .abw | Text | AbiWord Document |
| .ac | Executable | Autoconf Script |
| .ac$ | Misc | AutoCAD Temporary File |
| .ac3 | Audio | Audio Codec 3 File |
| .ac5 | Image | ArtCut 5 Document |
| .ac6 | Image | ArtCut 6 Document |
| .acb | Misc | AOL Cab Launcher |
| .acc | Data | Graphics Accounts Data File |
| .accdb | Data | Access 2007 Database File |
| .acd | Audio | ACID Project File (Most common) |
| .ace | Compressed | WinAce Compressed File |
| .acfm | Font | Adobe Composite Font Metrics File |
| .acl | Misc | AutoCorrect List File |
| .acr | Image | American College of Radiology Format (Most common) |
| .acrodata | Settings | Acrobat Data File |
| .acs | Misc | Agent Character File |
| .act | Text | FoxPro Documenting Wizard Action Diagram (Most common) |
| .action | Executable | Automator Action |
| .acx | Game | Atari ST Program |
| .ad | Misc | After Dark Screensaver |
| .ada | Developer | Ada Source Code |
| .adb | Developer | Ada Body File |
| .adc | Image | Scanstudio 16 Color Image |
| .add | Misc | Dynamics AX Developer Documentation File |
| .ade | Data | Access Project Extension |
| .adf | Disk | Amiga Disk File |
| .adg | Audio | Ableton Device Group |
| .adi | Image | AutoCAD Device-Independent Binary Plotter File (Most common) |
| .adm | System | Administrative Template File (Most common) |
| .adp | Data | Access Project |
| .adr | Web | Opera Bookmarks File |
| .ads | Developer | Ada Specification File |
| .adt | Data | ACT! Document Template (Most common) |
| .adx | Data | Approach Index File |
| .adz | Disk | Compressed Amiga Disk File |
| .aea | Settings | Ae Timer Alarm Document |
| .aep | Video | After Effects Project (Most common) |
| .afm | Font | Adobe Font Metrics File |
| .afp | Encoded | FileProtector Encrypted File (Most common) |
| .afploc | Misc | Apple Filing Protocol Location |
| .aft | Data | Ancestry.com Family Tree Database |
| .agi | Developer | Asterisk Gateway Interface File |
| .agif | Raster Image | Active GIF Creator Project |
| .agp | Raster Image | ArtGem Project File |
| .ahd | Misc | Dynamics AX Online Help Data Fil |
| .ahi | Misc | Dynamics AX Online Help Index File |
| .ahk | Executable | AutoHotkey Script |
| .ahl | Settings | eMule Metadata File |
| .ahs | Settings | Adobe Halftone Screen File |
| .ahx | Audio | WinAHX Tracker Module |
| .ai | Vector Image | Adobe Illustrator File |
| .aic | Raster Image | Advanced Image Coding File |
| .aif | Audio | Audio Interchange File Format (Most common) |
| .aifb | Data | AIF Builder Project File |
| .aifc | Audio | Compressed Audio Interchange File |
| .aiff | Audio | Audio Interchange File Format |
| .aim | Misc | AOL Instant Messenger Launch File (Most common) |
| .ain | Compressed | AIN Compressed File Archive |
| .aip | Plugin | Illustrator Plug-in |
| .air | Executable | Adobe AIR Installation Package |
| .ais | Image | ACDSee Image Sequence (Most common) |
| .ajp | Video | CCTV Video File |
| .akp | Audio | Akai Sampler File |
| .al | Audio | A-Law Compressed Sound Format |
| .alaw | Audio | A-Law Compressed Sound Format |
| .alc | Data | Dynamics AX Label Description File |
| .ald | Data | Dynamics AX Application Label Data File |
| .ali | Data | Dynamics AX Label Index File |
| .all | Audio | Cubasis Project File |
| .alt | Misc | Dynamics AX Temporary File |
| .alz | Compressed | ALZip Archive |
| .am4 | Developer | AutoPlay Media Studio 4 Project File |
| .am5 | Developer | AutoPlay Media Studio 5 Project File |
| .am6 | Developer | AutoPlay Media Studio 6 Project |
| .am7 | Developer | AutoPlay Media Studio 7 Project |
| .amb | Data | AIMMS Model File |
| .amf | Audio | Advanced Module File |
| .amfm | Font | Adobe Multiple Font Metrics File |
| .amr | Audio | Adaptive Multi-Rate Codec File |
| .ams | Settings | Adobe Monitor Setup file (Most common) |
| .amu | Image | Sony Photo Album |
| .amv | Video | Anime Music Video File |
| .amx | Video | Adobe Motion Exchange File (Most common) |
| .amxx | Plugin | AMX Mod X Plugin File |
| .an8 | Image | Anim8or File |
| .ani | System | Windows Animated Cursor |
| .anm | Image | 3D Animation File |
| .anme | Data | Anime Studio Project |
| .ann | System | Help Annotations |
| .ans | Text | ANSI Text File |
| .aob | Audio | DVD-Audio Audio Object File |
| .aod | Misc | Dynamics AX Object Data File |
| .aoi | Misc | Dynamics AX Application Object Index File |
| .aol | Misc | America Online File |
| .ap | Web | Active Page |
| .apa | Developer | RSView Development Project Archive |
| .ape | Audio | Monkey's Audio Lossless Audio File (Most common) |
| .api | Plugin | Acrobat Plug-in |
| .apk | Executable | Android Package File |
| .apng | Raster Image | Animated Portable Network Graphic |
| .app | Executable | Mac OS X Application (Most common) |
| .applescript | Executable | AppleScript File |
| .apr | Data | ArcView Project File |
| .apz | Compressed | Autoplay Media Studio Exported Project |
| .ar | Compressed | Unix Static Library |
| .arc | Compressed | Compressed File Archive (Most common) |
| .arch00 | Game | F.E.A.R. Game Archive |
| .ard | Image | ArtiosCAD Workspace File |
| .arf | Video | WebEx Advanced Recording File |
| .ari | Compressed | ARI Compressed File Archive |
| .arj | Compressed | ARJ Compressed File Archive |
| .ark | Compressed | PowerDesk Pro Archive |
| .aro | Web | SteelArrow Web Application File |
| .arp | Settings | Advanced RAR Password Recovery Setup |
| .arr | Image | Amber Graphic File (Most common) |
| .art | Vector Image | Art Document (Most common) |
| .as | Developer | ActionScript File |
| .asa | Web | ASP Configuration File |
| .asat | Image | Assemble SAT 3D Model File |
| .asc | Text | ASCII Text File (Most common) |
| .ascii | Text | ASCII Text File |
| .ascx | Web | Active Server Custom Control |
| .ase | Audio | Velvet Studio Sample (Most common) |
| .asf | Video | Advanced Systems Format File |
| .ashx | Web | ASP.NET Web Handler File |
| .ask | Data | askSam Database |
| .asl | Settings | Photoshop Style |
| .asm | Developer | Assembly Language Source Code File (Most common) |
| .asmx | Web | Active Server Method File |
| .asp | Web | Active Server Page |
| .aspx | Web | Active Server Page Extended |
| .asr | Web | ActionScript Remote Document |
| .ast | Settings | Adobe Color Separations Table (Most common) |
| .asx | Video | Microsoft ASF Redirector File |
| .atf | Settings | Photoshop Transfer Function File |
| .atn | Settings | Photoshop Actions File |
| .atom | Web | Atom Syndication Format |
| .atr | Disk | Atari Disk Image |
| .atrac | Audio | Sony ATRAC Audio File |
| .atx | Plugin | Animation Master Plugin File |
| .aty | Text | Association Type Placeholder |
| .atz | Misc | Atomic Time Zone File (Most common) |
| .au | Audio | Audio File |
| .au3 | Developer | AutoIt v3 Script |
| .aud | Audio | Video Game Compressed Audio File |
| .aup | Audio | Audacity Project File |
| .avb | Video | Avid Bin File |
| .avi | Video | Audio Video Interleave File |
| .avl | Misc | ArcView Legend File |
| .avr | Audio | Audio Visual Research File |
| .avs | Video | AviSynth Script File <font color="#00AA33">(Most common)</font> |
| .avs | Video | AviSynth Script File (Most common) |
| .awc | Misc | Emulex AWC Firmware Update File |
| .awd | Image | FaxView Document (Most common) |
| .awg | Data | Activeworlds Object Group File |
| .awk | Executable | AWK Script |
| .ax | Plugin | DirectShow Filter |
| .axm | Video | AXMEDIS Object |
| .axx | Compressed | AxCrypt Encrypted File |
| .azw | Data | Amazon Kindle eBook File |
