About this tool
Old camcorder footage and legacy downloads often live in AVI files that phones and modern editors refuse. Converting to MP4 with H.264 makes them playable on anything and usually shrinks them substantially at the same time.
About the formats: AVI is Microsoft's 1992 video container. It is still common for old camcorder footage and legacy downloads, but the files are large and mobile support is poor. MP4 is the universal video container, usually holding H.264 video and AAC audio. It plays on every phone, browser, TV, and editing program, which is why most platforms ask for it.
Everything happens inside your browser. Your file is never uploaded to a server: the conversion runs on your own device using WebAssembly, and the result is downloaded straight from memory. Close the tab and nothing is left behind.
How to use it
- Drop your AVI files into the box above, or click to browse. Nothing is uploaded.
- Adjust the options if you want; the defaults suit most files.
- Click Convert to MP4 and wait a moment.
- Download the results individually or all at once as a ZIP.
Frequently asked questions
Will my AVI be re-encoded?
Usually yes, because AVI typically contains DivX/Xvid or DV video that MP4 players do not support. H.264 or HEVC streams are copied without re-encoding.
Why does re-encoding take so long?
Encoding video in the browser runs on a single CPU core, so a re-encode processes roughly real time or slower for 1080p footage. Container swaps (stream copy) are near instant. Keep clips short or lower the resolution when you need speed.
Is this really free?
Yes. The site is supported by ads, and there are no limits on how many files you convert.
Are my files uploaded anywhere?
No. The converter runs entirely in your browser. Files stay on your device, which also makes it faster than upload-based converters for anything larger than a few megabytes.
Is there a file size limit?
The only limit is your device's memory. Images and audio of any normal size are fine; for video, files under about 500 MB work well on most laptops and phones.
Which browsers are supported?
Current versions of Chrome, Edge, Firefox, and Safari on desktop and mobile. Very old browsers without WebAssembly support will not work.