pfcalc - pipe friction calculator using the Darcy-Weisbach equation


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).
The program is written in the C programing language and can be compiled on all POSIX operating systems (Linux/BSD/Unix-like OSes) and also on 32-bit / 64 bit MS Windows (NT/2000/XP/Vista/7). Also it has been reported to compile and run on OS/2.
Data can be fed through command line arguments or can be read from a comma separated values file (csv). This is a text file that contains values separated by commas and can be exported from various spreadsheet programs. Every line is a data set that contains the following values, in this order: diameter, length, roughness, elevation, flow-rate, minor loss coefficient (K-factor), temperature. The program will read the file, make a calculation for every data set and print the result. Calculation results can be exported to a csv file that will contain a result per line, with values in this order: diameter, length, roughness, flow, temperature, velocity, Reynolds number, Darcy factor, hydrostatic pressure loss, minor pressure loss, major pressure loss.
The formulae used by pfcalc can be downloaded in pdf and odf formats. Detailed information about the calculation method can be found in the math section of this site.

User Guide

Altough pfcalc has been designed as a computational back-end on which to build more complex GUI applications, it can also be used directly from the command prompt or a terminal (on unix-like operating systems). Being a command line program, pfcalc is a versatile and efficient tool for scripting and integrating into complex application suites.
More information can be found in the user guide section of this website.


100% FREE award granted by Softpedia - Windows version
100% FREE award granted by Softpedia - Mac version


The following pfcalc screenshots are taken from a Linux system, but the program output is similar on all supported platforms.

Help screen:

screenshot of pfcalc help screen

Running with data from command line arguments:

screenshot of pfcalc running with command line arguments

Running with data from a csv file:

screenshot of pfcalc running with data from a csv file

Download - How to get

Current version is 1.0 and is available for download. There are two versions, one for 32 bit MS Windows and one for unix-like systems.
Note that the only supported download locations are the Sourceforge site and it's mirrors. Packages downloaded from other sites might contain malware or spyware. To make sure that you are installing the original software you can check the md5 sum of the packages. This are provided automatically by Sourceforge by viewing the detailed information of a file. Also, since pfcalc 0.6 every file made available for download has a corresponding md5 checksum file.
Note: there is no package available for 64 bit MS Windows, but you can build it from the 32 bit package, which includes all necessary files.

GUI front-ends

Currently there are two official front-ends for pfcalc:

Qpfcalc main window:

screenshot of qpfcalc main window

gpfcalc main window:

screenshot of gpfcalc main window

Sample files

Sample files can be downloaded for pfcalc csv and Qpfcalc pfc file formats and gpfcalc configuration file format.

Legal stuff


pfcalc-logo gpfcalc-logo qpfcalc-logo Qpfcalc, gpfcalc and pfcalc and their respective logos are © sargas at and are distributed under the GNU General Public License V3.0. The Windows version of Qpfcalc 1.6 is bundled with the zip/unzip utilities which are distributed under the Info-Zip license, and with the phonon module, distributed under the GNU Lesser General Public License.

Creative Commons License
This web site is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.


There are several ways for contacting the maintainer of pfcalc:

Last update

This page was last updated on 07/04/2012.

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