AVI to MP4 Converter

Convert a legacy .avi into a modern MP4 that plays anywhere and takes less space. Done on your device — nothing is uploaded.

Drop your file here, or click to choose Processed privately in your browser — nothing is uploaded

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100% private. Your file is processed in your browser with ffmpeg (WebAssembly) and is never uploaded. Big or long files take longer and use more memory — for those, trim first.

How to Use the AVI to MP4 Converter

Three steps, all in your browser.

1

Load your AVI

Drag a .avi file onto the box or click to choose one. AVI is an older Windows video format.

2

Convert to MP4

Click Convert. The tool re-encodes the video to H.264 and the audio to AAC in an MP4 container.

3

Download the MP4

Preview and download the .mp4 — smaller, modern and playable on current phones, players and the web.

Frequently Asked Questions

How do I convert AVI to MP4?
Load your .avi file and click Convert. The tool re-encodes it to an MP4 with H.264 video and AAC audio in your browser, then lets you preview and download it. No install and nothing uploaded.
Why convert AVI to MP4?
AVI is an old container that often uses dated codecs, producing large files that modern phones, browsers and editors may not play. MP4 with H.264 is smaller and far more compatible, so old clips become easy to watch, share and edit.
Is my video uploaded anywhere?
No. Everything runs locally with ffmpeg compiled to WebAssembly. Your file is never uploaded, logged or stored, so it’s safe for personal footage, and it works offline once loaded.
Will the file get smaller?
Usually, yes. Older AVI files are frequently encoded inefficiently, so re-encoding to H.264 commonly produces a noticeably smaller MP4 at similar visual quality.
Is there a size limit?
There’s no hard limit, but because the work happens in your browser, very large or long files use more memory and take longer to convert. Shorter clips finish quickly.

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