How to Convert AVI to MP4 (Modernize Old Video Files)

AVI files are a blast from the past. Microsoft created the format back in 1992, and while it served its purpose for decades, it has been largely replaced by MP4 for good reason. If you have a collection of old AVI files, converting them to MP4 saves storage space and makes them playable on modern devices.

Why AVI Files Are So Big

Many AVI files use older codecs with poor compression efficiency. A 2-hour video that is 4GB as an AVI might be just 1.5GB as MP4 with H.264 encoding, at similar or better visual quality. The newer codecs are simply much smarter about what data to keep and what to discard.

How to Convert

1. Go to Filoshi's AVI to MP4 converter
2. Drop your AVI file onto the page
3. Click Convert
4. Download your smaller, more compatible MP4

The converter runs entirely in your browser. No uploads, no waiting for server processing.

What to Expect

Unlike MKV to MP4 (which can often be remuxed losslessly), AVI to MP4 almost always requires re-encoding because AVI files typically use codecs that MP4 does not support natively. The re-encoding process takes longer but produces a much better file.

You will typically see:

• 50 to 70 percent reduction in file size
• Better color accuracy with modern encoding
• Universal playback on phones, tablets, and smart TVs

Batch Converting Old Videos

If you have an entire hard drive of old AVI files, the Filoshi desktop app can convert them all at once. Just drag the folder in, select MP4, and let it work through the collection. Perfect for digitizing old home videos or archiving a legacy media library.