Audio & video

Convert AVI to MP4 in your browser

Turn an AVI video into MP4 with local browser processing. AVI files can contain many codecs, so compatibility depends on the source variant and the memory available on this device.

No server upload No signup Up to 100 MB per file

Drag files here

This tool processes one file at a time.

AVI · Up to 100 MB per file

Local browser processing — Source files are not sent to our server for conversion.

How to convert AVI to MP4

Make an MP4 copy of a compatible AVI file in four steps.

Choose one AVI video from your device.
Review the file-size and estimated-memory guidance before starting.
Convert locally and leave this tab open until processing completes.
Download the MP4, then verify its duration, picture and sound in your usual player.

AVI and MP4 explained

AVI is an older container with many possible codecs, while MP4 is a common container for current playback and publishing workflows.

AVI video: AVI
MP4 video: MP4

The file extension describes the container, not the exact codec stored inside it.
Uncommon, lossless, protected or damaged AVI variants may be rejected instead of producing an unreliable file.

Good reasons to change AVI to MP4

An MP4 copy can make an older video easier to open or upload.

Playing an AVI file on a phone, tablet or browser that does not recognize it.
Preparing video for a web form, presentation or social platform that requests MP4.
Creating a current-format working copy while keeping the original AVI archived.

Check the converted video

Re-encoding is not lossless and output size is not guaranteed to be smaller.

Watch for frame-rate changes, audio sync and fine detail before sharing the result.
For a large file, close unused tabs and prefer a desktop device with sufficient free memory.

Local AVI processing

AVI decoding and MP4 creation run in the current tab without uploading the source file.

A same-origin media-engine asset may be fetched on first use, but file names, media bytes and metadata are not included in that request.
Clear the job after downloading when you use a shared device.

FAQ

Frequently asked questions

Why can one AVI convert while another cannot?

AVI files can use different codecs. The local engine may support one combination but not another, even when both files have the same extension.

Does AVI to MP4 reduce the file size?

It may, but size depends on the source and the encoding result. The tool does not promise a smaller file.

Can I close the tab during conversion?

No. Processing runs in this tab, so keep it open until the result is ready or cancel the job first.