Best Video Resolution for Smaller Files
Resolution is not file size by itself, but fewer pixels are easier to encode well with a limited bitrate.
1080p for detail
Use 1080p when text, UI elements or a large-screen viewing experience matters and the duration is modest.
720p for everyday sharing
720p is often the useful middle ground for chat, email and previews. It remains clear on many screens while reducing encoding work.
480p and 360p for tight limits
Lower resolutions are appropriate for long clips with very small size budgets. They are preferable to a blocky high-resolution encode at the same bitrate.