pfcalc stands for pipe friction calculator and is a CLI program that computes pressure drop in piping systems using the Darcy-Weisbach equation. The program is capable of computing minor and major pressure losses (pipe friction losses) for flow in pipes and ducts. The aim is to provide an open source alternative to similar proprietary software. The intended user base is made of those people working in the fields of mechanical and civil engineering, who need to estimate pressure drop in new or existing piping systems. Since the program and it's GUI front-ends are open source software, the users can study the inner workings and decide for themselves if the calculations made with pfcalc are accurate. Also, the software is free, as in beer and as in speech, and can be used, modified and distributed according to the GNU General Public License (see the legal stuff paragraph below).