A file with the .avi file extension is an Audio Video Interleave file. AVI is a commonly used video format that contains both audio and video.

What Is an AVI File?

First developed in 1992 by Microsoft, AVI is the standard video format for Windows machines. The file is saved in a multimedia container format that stores audio and video using a variety of codecs, like DivX and XviD.

An AVI file uses less compression to store files and takes up more space than many other video formats---like MPEG and MOV. AVI files also can be created without the use of compression at all. This makes the files lossless, which results in immensely larger file sizes --- approximately 2-3 GB per minute of video. A lossless file will not lose quality over time, regardless of how many times you open or save the file. Additionally, this allows for playback without the use of any codecs.

How Do I Open an AVI File?

AVI is a proprietary file format created by Microsoft, so if you plan on opening one outside of Windows, you'll need a third-party application to handle playback.

If you're using Windows, all you have to do is double-click the file to open it in Windows Media Player.

If for some reason that doesn't work, you can right-click the file, point to the "Open With" menu, and then click "Windows Media Player" or whatever other supported app you prefer.

If you're using macOS or Linux, things aren't that easy since those platforms don't have built-in apps with AVI support. Instead, you'll need to download a third-party app. We highly recommend VLC Player. It's fast, open-source, free and you can use it on Windows, macOS, Linux, Android, and iOS.

VLC also supports pretty much every file format out there and is a highly capable player. Even Windows users might prefer it to a less-capable app like Windows Media Player.