AVI Converter

Choose your files and pick an output format. AVI Converter works entirely in your browser — nothing is uploaded.

No uploadNo limitsNo sign-upFree
Processed locally in your browser — your files are never uploaded.

How to use the AVI Converter converter

  1. Add filesClick “Choose Files” or drag them in. Each file is detected automatically, and you can mix different formats in one batch.
  2. Pick the output formatUse the “to” menu next to each file to choose the target format (AVI is preselected).
  3. Convert and saveHit “Convert”. Everything is processed on your device, then you can download each result or a ZIP of all of them.

About AVI

AVI Audio Video Interleave

AVI is one of the oldest Windows video containers. It is widely supported by legacy players, DVD players and older software, but files are larger than modern MP4 at the same quality.

Compression
Varies (DivX/Xvid/MJPEG)
Features
Video + audio
Origin
1992, Microsoft
Best for
Older players and software

Why use ConvertMathly?

100% private

Files are processed on your device and never uploaded. Close the tab and they are gone.

No limits, no sign-up

No account, no daily cap, no queue and no watermark — convert as much as you want.

Powered by FFmpeg

The same engine used by professional video tools, running in your browser via WebAssembly.

Works everywhere

Windows, Mac, Linux, Chromebook, iPhone and Android — any modern browser, nothing to install.

Frequently asked questions

What formats does the AVI Converter support?

It accepts MP4, MOV, AVI, MKV, WEBM, FLV, WMV, 3GP, M4V, MPEG, MPG, TS, MTS, M2TS and more, and can output MP4, WEBM, MOV, AVI, MKV, FLV, WMV, 3GP, GIF, MP3, WAV, AAC, OGG, M4A, FLAC.

Is it really free?

Yes. ConvertMathly is free with no sign-up, no watermarks and no limits. The site is supported by ads.

Are my files private?

Completely. Conversion happens inside your browser — files are never uploaded to any server.

Why does the first video or audio conversion take longer?

A one-time download of the FFmpeg engine (~30 MB) is needed. It is cached afterwards, so later conversions start instantly.

Does it work on iPhone and Android?

Yes, the converter works in Safari, Chrome, Firefox and Edge on phones, tablets and computers.

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