Convert MP4 to AVI
This free MP4 to AVI converter changes your MPEG-4 Part 14 (.mp4) file into a Audio Video Interleave (.avi) file, right in your browser. There is nothing to install, no account to create, and no limit on how many files you convert.
100% private. Your file is processed locally in your browser with WebAssembly — it is never uploaded to a server, stored, or seen by anyone.
The conversion runs on your own device using ffmpeg compiled to WebAssembly (ffmpeg.wasm), so your file is never uploaded to a server. AVI is best for older Windows software and archives, which is the usual reason to convert from MP4.
Why convert MP4 to AVI?
- Note: AVI has narrower support than MP4 - convert only when a specific app or workflow needs it.
- The video is re-encoded to efficient H.264, so the AVI file is usually about the same size as your MP4.
- Pick AVI when you need a file made for older Windows software and archives.
MP4 vs AVI
| Property | MP4 | AVI |
|---|---|---|
| Full name | MPEG-4 Part 14 | Audio Video Interleave |
| Container | MPEG-4 | AVI |
| Typical codec | H.264 + AAC | MPEG-4 / MJPEG |
| Compatibility | Universal | Limited |
| Relative size | Small | Largest |
| Best for | Sharing and playing almost anywhere | Older Windows software and archives |
How to convert MP4 to AVI
Add your MP4 file
Drag and drop your .mp4 file onto the upload area, or click to browse and pick it from your device.
Start the conversion
Click "Convert to AVI". Everything runs locally with ffmpeg compiled to WebAssembly (ffmpeg.wasm) - your file stays on your device.
Wait a few seconds
A progress bar shows the conversion. The first run is slightly slower while the engine loads, then it is cached.
Download your AVI file
When it finishes, download the .avi file straight to your device.
Frequently asked questions
Is this MP4 to AVI converter free?
Are my files uploaded to a server?
Will I lose quality converting MP4 to AVI?
Will the file get smaller or larger?
What is the difference between MP4 and AVI?
How long does the conversion take?
Related conversions
Need more formats or options? Use the full Change Video Format.