Software - > BitCalc

Yes, there are many bit rate calculators, but may be a couple o things make this one I have made a little more usefull:

1. Once the video bitrate is given, you can change it (to round it or whatever) and the size of the final file will reflect it.
2. It Doesnt need any runtime file, is a stand alone exe
3. Delphi code is included.
4. Spanish / English interface.