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Pump Head Requirement Calculator

Work out pump head requirement instantly with clear inputs, formula shown and shareable results.

About Pump Head Requirement Calculator

Pump head is the static lift plus the friction the pipework imposes. Friction comes from Hazen-Williams with a C factor of 140 for plastic pipe, and a further 20 percent is added for bends, valves and fittings. Hydraulic power is rho g Q H, divided by pump efficiency to give shaft power.

Formulas

Hazen-Williams

hf = 10.67 L Q^1.852 / (C^1.852 D^4.87), Q in m³/s and D in m

Power

kW = 9.81 x Q L/s x total head / (1000 x efficiency)

Worked example

With the default values below, Pump Head Requirement Calculator returns Total pump head required of 33.75. Change any input above and every figure here is recalculated in your browser.

Inputs used

Static headminimum 0 m
30 m
Total pipe lengthminimum 0.1 m
60 m
Design flowminimum 0.01 L/s
3 L/s
Pipe internal diameterminimum 5 mm
50 mm

Results

Total pump head required
33.75 m
Friction head
3.75 m
Pipe velocity
1.528 m/s
Shaft power at 65 percent efficiency
1.528 kW

Step by step

  1. 1Values used
  2. 2Hazen-Williams
  3. 3Power
  4. 4Total pump head required= 33.75 m
  5. 5Friction head= 3.75 m
  6. 6Pipe velocity= 1.528 m/s
  7. 7Shaft power at 65 percent efficiency= 1.528 kW

Assumptions and limits

  • The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is the Pump Head Requirement figure worked out?

hf = 10.67 L Q^1.852 / (C^1.852 D^4.87), Q in m³/s and D in m. Pump head is the static lift plus the friction the pipework imposes.

Why add a percentage for fittings?

Each bend, tee and valve behaves like extra pipe length. On a compact installation with many fittings the allowance can exceed the straight pipe loss, so it should be assessed properly rather than assumed.

What values do I need to enter?

This calculator takes 4 inputs: Static head, Total pipe length, Design flow, Pipe internal diameter. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.

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