Convert AVI to MP4 Online
MP4 to AVIConvert AVI video to MP4 directly in your browser. Free, no signup, and your file is never uploaded.
Click to upload or drag a file here
Supported: AVI · Processed entirely in your browser
Converted entirely in your browser using a WebAssembly build of FFmpeg — your file is never uploaded anywhere. Larger files take longer and use more memory.
AVI to MP4 converts an older AVI video into the far more widely-supported MP4 format, which plays natively on phones, browsers and most modern devices where AVI often doesn't anymore.
Why does AVI play so inconsistently on modern devices?
AVI is a much older container format, and modern phones, browsers and streaming platforms are built and optimized around MP4 as the default expectation — AVI support has quietly faded from many newer apps and devices over the years, which is exactly why an old AVI file that used to play fine can suddenly stop working on a new phone or upload form.
Will the video quality change when converting from AVI to MP4?
It depends on how the original AVI was encoded — if it used an older, less efficient codec, MP4 can often deliver similar or better visual quality at a smaller file size, since video compression has improved substantially since AVI's early-1990s design.
Is this private, and does the video get uploaded anywhere?
No — conversion happens entirely in your browser, so the video is never uploaded to a server; it's also free, with no sign-up and no limit on how many files you convert.
Why did one of these formats become a single company's product and the other an international standard?
They came from genuinely different starting points. AVI was released by Microsoft alone in November 1992, built quickly and specifically as a competitive answer to Apple's QuickTime — a single company's proprietary format designed for a single operating system. MP4 took the opposite path: the Moving Picture Experts Group, an international standards body, developed it through the late 1990s under a team led by Touradj Ebrahimi and Fernando Pereira, and it became a formal ISO/IEC international standard in 1999 — a format built collaboratively across the industry rather than owned by one vendor. That structural difference — one company's product versus an open industry standard — is a big part of why MP4 ended up with the broader, longer-lasting device support AVI never quite achieved.
Is AVI to MP4 free to use?
Yes. AVI to MP4 is completely free, with no sign-up and no usage limits.
Do I need to install any software?
No. AVI to MP4 runs directly in your web browser — nothing to download or install.
Is my data kept private?
Everything happens on your device. We never receive or store the file or text you enter into AVI to MP4.