| Расширение | Форматы | К-ство форматов |
|---|---|---|
| arc | Compressed File Archive | 1 |
| arw | Sony Digital Camera RAW image file, ArtStudio image file | 2 |
| asc | ActionScript Communication File, ASCII text file | 2 |
| asd | Microsoft Word auto-save document file | 1 |
| asf | Advanced Systems Format File | 1 |
| ashx | ASP.NET Web Handler File | 1 |
| asm | Assembly Language Source Code, Solid Edge Assembly Document | 2 |
| asp | Active Server Page | 1 |
| aspx | Active Server Page Extended ASP.NET script file | 1 |
| asx | Microsoft Advanced Streaming Redirector file | 1 |
| att | Web Form Data file | 1 |
| avb | Avid Bin File, Chat character file | 2 |
| avc | Kaspersky Virus Database, MPEG-4 AVC movie file, Avid Media Composer Script | 3 |
| avi | Audio Video Interleaved | 1 |
| avs | AviSynth Script File, AVS preset file, Avid Project Preferences File, Adobe Photoshop Variations File | 4 |
| awb | AMR-WB Audio File | 1 |