Pump Power Calculator
Calculate hydraulic power, shaft power, impeller diameter and affinity law performance changes for centrifugal pumps.
1. Impeller Diameter Estimation from Head & RPM
Estimated Impeller Diameter
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Tip Speed
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Step-by-Step Method
- Estimate peripheral velocity using pump head relation.
- Use centrifugal pump velocity-head equation.
- Calculate impeller diameter from RPM.
- Verify against practical pump manufacturer ranges.
Approximate formula:
D = (84.6 × √H) / N
Where D = Impeller Diameter (m), H = Head (m), N = RPM.
2. Pump Affinity Law Calculator
New Flow
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New Head
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New Power
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Pump Affinity Laws
- Flow ∝ RPM
- Head ∝ RPM²
- Power ∝ RPM³
Affinity laws are commonly used for VFD-controlled centrifugal pumps.
Pump Engineering Guide
Pump power calculation is important for proper motor sizing, energy optimization and hydraulic system design. Oversized pumps increase operating cost and reduce reliability.
Centrifugal pumps are widely used in chemical plants, water treatment, oil & gas, boiler feed systems and cooling water applications.
This calculator uses standard engineering equations based on hydraulic energy balance and centrifugal pump affinity laws.
Best Practices
- Select pumps near BEP (Best Efficiency Point)
- Avoid excessive throttling losses
- Use VFD for variable flow applications
- Check NPSH requirements carefully
- Verify power margins before motor selection