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AVI to MP4 Online Free — PrivaTools

TL;DR: Upload your file, click AVI, and download the result — free, browser-based, no sign-up, no watermarks. Files are processed and discarded immediately.

Convert AVI to MP4 online for free — modernize old AVI videos to H.264 MP4 for streaming-friendly playback on phones, browsers, and modern TVs.

AVI to MP4 is one of 179+ free file utilities on PrivaTools. The entire stack is open source under the MIT license, so the privacy guarantees can be audited end-to-end. You can also run all 179 tools on your own infrastructure with one docker compose command.

How to Use AVI to MP4

  1. Upload an AVI — Drop an .avi video — typical for older Windows captures.
  2. Convert and download — Click Convert. The result is an MP4 with H.264 video and AAC audio, ready for streaming on phones, browsers, and modern TVs.

Frequently Asked Questions

Why convert AVI to MP4?

AVI is an old Microsoft container with poor support for modern codecs and metadata. MP4 is the universal standard — every modern device, browser, and editor plays it.

What if my AVI uses DivX or Xvid?

FFmpeg re-encodes the video to H.264 inside the MP4 container, so any source codec is handled.

Will the file get bigger or smaller?

Usually similar or smaller. Old AVIs often used inefficient codecs; modern H.264 typically achieves the same quality at a smaller size.

Last reviewed 2026-05-01 by the PrivaTools maintainers. Source code on (MIT-licensed, self-hostable).

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