Get your video under X's file size limit

X has two separate ceilings for video, and only one of them is about file size. Without Premium you are held to a short clip; with Premium the allowed length and size both jump. Which ceiling you hit first depends on your account, so it helps to know both before you compress.

Why X has this limit

X's help page states the limits by plan and does not explain them. The pattern it shows is that length and size are tied to Premium: an account without Premium can upload videos up to 140 seconds long and 512 MB, while Premium accounts can upload videos shorter than 4 hours at 1080p with a maximum file size of 16 GB.

Source: help.x.com

What FitSize does with your file

FitSize defaults to the limit for accounts without Premium, since that is what most accounts have, and offers the Premium limit as a one-click option. Length is not something compression can change, so if your clip is longer than the account allows, trimming it comes first; compression only helps with the file size.

Best fit for a 30-second clip at 512 MB: 1080p at Balanced quality (that resolution holds up to 12 min 56 s). Best fit for a 2-minute clip at 512 MB: 1080p at Balanced quality (that resolution holds up to 12 min 56 s).

Your file never leaves your device. It is read and compressed by your browser, and nothing is uploaded to a server.

Three things to watch on X

X limits by account type