AVI to MP4 Converter — Free, No Upload
Modernise legacy AVI files into smaller, widely supported MP4.
Drop a file here
or click to choose a file
Runs on your device Your file is processed by your own browser and is never uploaded to a server.
Short answer
AVI files can be converted to MP4 in a browser without uploading. AVI is a 1992 Microsoft container that usually holds older, inefficient codecs such as DivX, Xvid or MJPEG. Re-encoding to H.264 inside an MP4 container typically cuts the file size substantially and makes the video playable on modern phones, browsers and televisions.
At a glance
| Accepts | AVI (DivX, Xvid, MJPEG and others) |
|---|---|
| Produces | MP4 (H.264 / AAC, faststart) |
| Processing | In your browser |
| Price | Free, no limits |
| Account | Not required |
AVI files are usually old, and their age shows in two ways: the codecs inside them are far less efficient than H.264, and modern devices frequently refuse to play them at all. Converting solves both problems in one pass.
Expect a noticeably smaller output file. An AVI encoded with Xvid or MJPEG often shrinks by half or more when re-encoded to H.264 at equivalent visual quality.
How to use it
- 1
Add the AVI file
Drop in the .avi file you want to modernise.
- 2
Choose quality
Balanced is a good default for archive footage.
- 3
Convert
The video is re-encoded to H.264 and the audio to AAC.
- 4
Download the MP4
Save the smaller, more compatible file.
Frequently asked questions
Why will my AVI not play on my phone or TV?
AVI commonly contains DivX, Xvid or MJPEG video, which modern mobile and TV hardware does not decode. MP4 with H.264 is supported by essentially all of it.
Will the MP4 be smaller than the AVI?
Usually much smaller. H.264 is far more efficient than the codecs typically found in AVI files, so a 50% or greater reduction is common.
Will converting improve the quality?
No. Conversion cannot recover detail that was never captured or was already lost. It improves compatibility and file size, not fidelity.
My AVI fails to convert. Why?
Some very old or proprietary codecs are not included in the browser engine. Playing the file in VLC and re-exporting it is the usual workaround.