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AVIWebM

Convert AVI to WebM

This free AVI to WebM converter changes your Audio Video Interleave (.avi) file into a WebM (.webm) 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.

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The conversion runs on your own device using ffmpeg compiled to WebAssembly (ffmpeg.wasm), so your file is never uploaded to a server. WebM is best for fast-loading web and HTML5 video, which is the usual reason to convert from AVI.

Why convert AVI to WebM?

  • WebM plays on more devices and apps than AVI, so it is the safer choice for sharing.
  • Re-encoded with VP9, the WebM file is often smaller than AVI at similar quality - handy for the web.
  • Pick WebM when you need a file made for fast-loading web and HTML5 video.

AVI vs WebM

PropertyAVIWebM
Full nameAudio Video InterleaveWebM
ContainerAVIWebM
Typical codecMPEG-4 / MJPEGVP9 / VP8 + Opus
CompatibilityLimitedWide
Relative sizeLargestSmallest
Best forOlder Windows software and archivesFast-loading web and HTML5 video

How to convert AVI to WebM

  1. Add your AVI file

    Drag and drop your .avi file onto the upload area, or click to browse and pick it from your device.

  2. Start the conversion

    Click "Convert to WebM". Everything runs locally with ffmpeg compiled to WebAssembly (ffmpeg.wasm) - your file stays on your device.

  3. Wait a few seconds

    A progress bar shows the conversion. The first run is slightly slower while the engine loads, then it is cached.

  4. Download your WebM file

    When it finishes, download the .webm file straight to your device.

Frequently asked questions

Is this AVI to WebM converter free?
Yes. It is completely free with no signup, no watermark, and no limit on how many files you convert. It is supported by ads, which keeps the conversion itself free.
Are my files uploaded to a server?
No. The conversion runs locally in your browser using ffmpeg compiled to WebAssembly (ffmpeg.wasm), so your file is processed in memory on your own device and is never uploaded, stored, or seen by anyone.
Will I lose quality converting AVI to WebM?
The video is re-encoded to WebM with a high-quality setting, so the result looks very close to the original AVI. Re-encoding is never bit-for-bit identical, but the loss is minimal.
Will the file get smaller or larger?
Usually smaller. WebM is re-encoded with VP9, an efficient web codec that often beats AVI on size at the same quality.
What is the difference between AVI and WebM?
AVI is Audio Video Interleave (an AVI container, typically MPEG-4 / MJPEG); WebM is WebM (a WebM container, typically VP9 / VP8 + Opus). WebM is best for fast-loading web and HTML5 video, while AVI is best for older Windows software and archives.
How long does the conversion take?
Most files finish in a few seconds to under a minute, depending on length and your device. The first conversion is a little slower while the engine downloads and caches, then later runs start instantly.

Related conversions

MP4 → WebMMOV → WebMMKV → WebMAVI → MP4AVI → MOVAVI → MKV

Need more formats or options? Use the full Change Video Format.