GIF or MP4: which should you use?

This is the biggest practical difference. MP4 uses a real video codec that describes motion between frames; GIF just stores lightly compressed stills. For the same photographic clip an MP4 is routinely five to ten times smaller. For flat-colour line art the gap is much narrower, and a short drawn loop can be a perfectly reasonable GIF.

A GIF frame is limited to 256 colours. Flat colour and hard edges — what a paint program produces — handle that limit fine. Photographic gradients, skies and skin tones show visible banding. MP4 keeps the full colour range, so footage and anything with gradients looks markedly better as video.

Only GIF can be transparent, and even then only with hard edges (see transparent GIFs). MP4 and WebM always have a solid rectangular background. If you need the animation to show the page behind it, you need a GIF.

A GIF plays inline, silently, on a loop, absolutely everywhere — email, old forums, documents, wikis. That universality is the reason the format refuses to die. MP4 needs something that plays video, which in practice means a modern site or app. Most large social platforms now take an uploaded GIF and quietly convert it to a video on their end anyway, so on those the choice matters less than it used to.

• Hand-drawn animation, a few seconds, looping — GIF.
• Needs a transparent background — GIF.
• Going in an email, a doc, a wiki, or an old forum — GIF.
• Converted from video footage — MP4.
• Longer than about five seconds — MP4.
• Full-colour, gradients, or you care about sharpness — MP4.

Everything in the studio exports to both from the same project, so you can make a GIF for the places that need one and an MP4 for the places that render it better. If a GIF you have made is too heavy, try the fixes in making a GIF file smaller first, and switch to MP4 if it still will not come down.