ClueLuma

Head versus speed calculator

Centrifugal head or pressure varies with the square of speed.

Units
Head2=Head1×(N2N1)2\text{Head}_{2} = \text{Head}_{1} \times \left(\frac{N_{2}}{N_{1}}\right)^{2}

Calculator

Enter the values you know and leave one box empty. Calculate finds the empty one, the result or any input.

ft or psi
rpm
rpm
ft or psi

Worked example

Given

  • Head1\text{Head}_{1} = 90 ft or psi
  • N2N_{2} = 1,400 rpm
  • N1N_{1} = 1,750 rpm
Head2=90×(14001750)2=57.6\text{Head}_{2} = 90 \times \left(\frac{1400}{1750}\right)^{2} = 57.6

Symbols and units

SymbolMeaningUnit
Head2\text{Head}_{2}new head or pressureft or psi
Head1\text{Head}_{1}initial head or pressureft or psi
N2N_{2}new speedrpm
N1N_{1}initial speedrpm

Related calculators

Results are estimates for study and screening. Check the inputs, units and assumptions before you use them for design, billing or contract decisions.