If you record videos of your desktop, especially the Terminal, it’s a challenge to get your window to fit properly in a 16:9 format. Without the proper tool, eyeballing a window to fit a certain resolution is a difficult task to do.
One of the tools I use to set my window to a resolution that I want is to use my browser as a guide. There are several websites out there that allow you to set your browser to any size or resolution. Head over to resizemybrowser.com. They have several presets in varying resolutions.
If you don’t like any of their presets, then you can create your own. In addition, you can also manually adjust your current window to any size you want. The website gives you feedback of your resolution in real time. Once you set your browser to the right size, then you can match your Terminal with the size of your browser.