How to Convert AVI to MP4 on iPhone

AVI is the format of old digital cameras, old downloads, and old family archives — and iPhones want nothing to do with it. Here's how to bring those videos into the present.

The quick answer

Bring the AVI file into the Files app, open it in Video To MP4, convert to MP4, and the clip becomes fully playable and savable to your Photos library.

Step-by-step: AVI → MP4

1. Transfer the AVI to your iPhone — AirDrop from a Mac, iCloud Drive, or any cloud storage app into Files.
2. Open Video To MP4 → Convert and select the AVI.
3. Pick MP4 and quality, then convert.
4. Save to Photos — the converted file now behaves like any iPhone video.

Why AVI aged out

AVI dates to 1992 — it predates streaming, phones, and modern compression. Files are larger than they need to be and support outside Windows is fading. MP4 gives you the same video in a smaller, universally supported package.

Old video, big file?

AVI's inefficient compression means converted files often shrink already — but if you're archiving lots of footage, run the result through compression too, or trim out the dead air first with the trim tool.