ASPE (American Society of Plumbing Engineers) has some wheels that they recently developed. I have not obtained one yet, so I do not know how user friendly they are. I still use the old method of counting and comparing to the tables in the code.
If you are sizing the water pipe, I use the code tables to get the fixture unit to flow rate conversion and then use the Bell & Gosset System Syzer to get the pipe size. I also sometimes use the Cameron Tables for the sizing.
Hope this helps.