They both show short moving clips, so why do messaging apps keep converting your GIFs to video? Because GIF and MP4 are built very differently.
The quick answer
- Use a GIF when you need something that autoplays and loops anywhere without a video player — chat, docs, READMEs, email.
- Use an MP4 when you care about file size and quality — social video, a website background, anything longer than a few seconds.
Why MP4 is so much smaller
GIF stores each frame with an old compression scheme capped at 256 colours. MP4 uses modern video compression that only stores what changes between frames, in full colour. The result: the same 3-second clip is often 5–10x smaller as MP4.
Best of both worlds
A common workflow is to keep an MP4 as your master and export a GIF only when a specific place needs one.
- Shrink a heavy GIF by converting it to GIF to MP4.
- Or go the other way with Video to GIF when autoplay-anywhere matters.
More detail in GIF vs MP4.