Enter Pump Data
Use any supported engineering units. The calculator converts everything internally before computing efficiencies and losses.
Example Data Table
| Case | Flow | Head | Shaft Power | Electrical Input | Hydraulic Power | Pump Efficiency | Overall Efficiency |
|---|---|---|---|---|---|---|---|
| Pump A | 72 m³/h | 28 m | 7.2 kW | 8.2 kW | 5.48 kW | 76.1% | 66.8% |
| Pump B | 95 m³/h | 34 m | 10.9 kW | 12.4 kW | 8.78 kW | 80.6% | 70.8% |
| Pump C | 48 m³/h | 18 m | 3.4 kW | 4.0 kW | 2.35 kW | 69.1% | 58.7% |
Formula Used
Hydraulic power
Ph = ρ × g × Q × H
Where ρ is density, g is gravity, Q is volumetric flow rate, and H is head.
Pump efficiency
ηpump = (Ph / Pshaft) × 100
This compares useful fluid power with the power delivered to the pump shaft.
Overall efficiency
ηoverall = (Ph / Pelectrical) × 100
This includes upstream motor and drive losses before shaft power reaches the pump.
Motor and drive efficiency
ηmotor+drive = (Pshaft / Pelectrical) × 100
This isolates how effectively the electrical system transfers power to the shaft.
Annual energy cost
Annual cost = Pelectrical × operating hours × electricity rate
This helps connect efficiency changes to yearly operating expense.
How to Use This Calculator
- Select whether shaft power, electrical input, or both are known.
- Enter flow rate, developed head, fluid density, and gravity.
- Provide available power information and confirm unit selections.
- Fill in motor and drive efficiency so missing power can be inferred when needed.
- Add annual operating hours and electricity rate for cost estimates.
- Press the calculate button and review the result section above the form.
- Use the CSV and PDF buttons to export the current report.
FAQs
1) What does pump efficiency mean?
It compares useful hydraulic power to supplied shaft or electrical power. Higher efficiency means more fluid energy and less wasted heat, friction, and motor loss.
2) Why can pump and overall efficiency differ?
Pump efficiency uses shaft power at the pump. Overall efficiency uses electrical input, so it also includes motor and drive losses before power reaches the pump shaft.
3) Which power basis should I use?
Use shaft power when you know brake power from tests. Use electrical input when you only know meter readings or motor nameplate data.
4) Why does density affect hydraulic power?
Hydraulic power depends on fluid weight flow. Denser liquids require more power to produce the same flow and head than lighter liquids.
5) Can I use feet, gpm, and horsepower?
Yes. The calculator converts common flow, head, density, and power units into SI values internally, then reports clear engineering outputs.
6) What if my calculated efficiency exceeds 100%?
That usually means inconsistent inputs, wrong units, or incorrect power measurements. Recheck flow, head, density, and whether power values are shaft or electrical.
7) How does annual energy cost help?
It shows the operating cost linked to electrical input. Small efficiency improvements can create large yearly savings when pumps run many hours.
8) Is this suitable for slurry or viscous fluids?
It is best for clean-fluid style energy estimates. Very viscous, multiphase, or solids-laden service may need correction factors and detailed manufacturer curves.