Convert AVI to WebM
From the format browsers never learned to the one they were built for — converted on your own device.
Drop your video or audio here
or
MP4, MOV, WebM, MKV, AVI, MP3, WAV and more — any size, no upload
🔒 Files never leave your device — everything runs in your browser.
AVI and WebM sit at opposite ends of video history: one predates the web-video era entirely, the other was designed for it. Converting bridges the whole span in one step — an old clip becomes a file a web page can embed and every current browser plays natively.
AVI needs the site's built-in decoding engine, which loads once on first use and then handles the formats of that era. The conversion re-encodes video and audio into WebM entirely in your browser — old family clips and archives never upload anywhere.
How it works
- Drop your file
Any common format, any size. Nothing is uploaded — the tool runs in your browser.
- Convert
Compatible files are repackaged instantly with zero quality loss; others are hardware-transcoded at high quality.
- Download
Your converted file is ready on your device — nothing to wait for, nothing to delete from a server.
Frequently asked questions
Why does the first conversion take a moment to start?
Browsers cannot read AVI natively, so the site loads its own decoding engine on first use — a one-time download of a few seconds. Conversions after that begin immediately.
Will an old AVI look better as WebM?
It will look the same — conversion preserves what the file contains, and cannot invent detail the original recording lacks. What changes is compatibility: the clip plays everywhere the web reaches.
Is WebM or MP4 the better destination for old AVI files?
MP4 for maximum device compatibility — TVs, phones, editing software. WebM for the open web — embedding in pages and platforms that prefer open formats. Both conversions are available; pick by destination.
Is my file uploaded to a server?
No. ConvertUno runs entirely in your browser on your own device. Your file never leaves your computer or phone — there is no upload at all.
Is it really free, with no watermark?
Yes. Processing happens on your device, so serving you costs us almost nothing — no watermark, no account, no file-size limit, no daily quota.