I found this to be handy and saves me time from squashing numbers to get the desired files size output I am looking for after the encoding is done. Even with h.265/x265 HEVC encoding.
BitrateCalc v1.1.0.0
Mirror 1 (http://www.digital-digest.com/software/BitrateCalc.html)
Mirror 2 (https://www.videohelp.com/software/BitrateCalc)
too bad this is no longer being developed
(https://www.allripped.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FHnrJ3TE.png&hash=5341fc14d069de1ed5f1ebfa9cc9a048)