Why does it take so long to upload a video on Facebook?

Video footage typically has a fairly large file size relative to its length (a 720p video of 10 minutes in length may be more than one gigabyte). This means that attempting to transfer video files to the internet can take a very long time.

Unfortunately, this is somewhat unavoidable. Even if you have a fairly fast internet connection, there is a limit to the speed at which the files will be received by Facebook and loaded onto their servers. Furthermore, if there is a large amount of activity on Facebook at the time (i.e. high demand on the servers) file transfers to the servers will be slowed down.