Online Hazen Williams pressure loss calculator

The Hazen-Williams pressure loss equation is used through the world for calculating the pressure loss in fire sprinkler systems, wet risers, fire hydrant systems and many other types of fire protection systems including low-pressure water mist.

Bellow, you will find an online calculator which you can use to calculate the pressure loss in a pipe using the Hazen Williams pressure loss equation.  The equation which we have used is based on the one found in EN 12845, NFPA 13 and NFPA 750 and uses the typical metric units of Bar and Litre per minute (L/min).


Then using the calculator please remember to use the internal diameter of the pipe and not the nominal otherwise the answer will not be valid.  You can find out more information about the Hazen-Williams pressure loss equation.  If you regularly need to use the HW to calculate pressure loss then we have a useful calculate Hcalc which you can download of free.

Contact Us

Canute LLP - footer logo

Canute LLP
15 Queen Square
Leeds, West Yorkshire
United Kingdom LS2 8AJ

t: +44 (0) 113 328 0350

Copyright © 2021, Canute LLP
Registered in England & Wales, Partnership No. OC305985 Protection Status