Mass Flow Calculator

Use the calculator below to determine the required flow rate in a heating system. To use, simply enter the heat requirement in the text input box and adjust the slider to the required temperature differential.

Please note that Java must be enabled on your browser in order to use this calculator. Java is available from here.

The volumetric flow rate in heating systems is expressed as:

Volumetric flow rate in heating systems equation


  • Q is the volumetric flow rate
  • h is the heat flow
  • cp is the specific heat capacity of the liquid
  • ρ is the density of the liquid
  • ΔT is the temperature differential
The heat transfer medium is assumed to be water, with a specific heat capacity of 4.186 joule/gram °C.


The software provided herein is provided free of charge and may be freely distributed so long as this disclaimer remains in place. Blaney Mechanical Ltd provide this software as is and do not express or imply any warranty of merchantibility nor any warranty of fitness for a particular purpose. If you wish to use this software, you should satisfy yourself that it is suitable for the intended purpose.

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