HandBrake

I recorded a short (small (less than 20 sec)) video and wanted to post to Discord channel for game bug reporting but I had to encode twice to get it down to 8.00MB (file requirements for Discord).......my question is, can we select what size to encode a video down to?

Do the size/time math and enter that as your bitrate target.

I have the answer in my head, but I'll just give you the formula.
Time (sec) x Bitrate (Mbps) x .125 = Size (MB)