Fuel Pump Horsepower Calculator

Calculator Input

Calculation mode

Flow rate per pump

Flow unit

Pressure unit

Differential pressure

Discharge pressure

Suction pressure

Total head

Head unit

Specific gravity

Pump efficiency (%)

Motor efficiency (%)

Service factor

Number of pumps

Reset

Example Data Table

Case	Mode	Flow	Pressure or Head	SG	Pump Eff.	Motor Eff.	Service Factor	Recommended hp
Fuel transfer skid	Differential pressure	120 gpm	65 psi	0.85	72%	91%	1.15	7.99 hp
Dual pump setup	Differential pressure	180 gpm	80 psi	0.84	70%	90%	1.15	15.33 hp per pump
Tank elevation duty	Total head	250 gpm	12 m head	0.84	68%	92%	1.20	4.00 hp
Trailer refueling line	Discharge minus suction	95 gpm	55 psi - 5 psi	0.83	75%	93%	1.10	4.37 hp

Formula Used

The calculator estimates horsepower from flow, differential pressure, density effect, and efficiency losses.

Hydraulic horsepower	Hydraulic hp = (Flow in gpm × Differential pressure in psi) ÷ 1714
Shaft horsepower	Shaft hp = Hydraulic hp ÷ Pump efficiency
Motor input horsepower	Motor input hp = Shaft hp ÷ Motor efficiency
Recommended motor horsepower	Recommended hp = Motor input hp × Service factor
Head conversion	Differential pressure in psi = (Head in ft × Specific gravity) ÷ 2.31

Use differential pressure when you already know pump pressure rise. Use discharge minus suction when both gauge readings are available. Use total head when the design is based on elevation and line losses.

How to Use This Calculator

Select the calculation mode that matches your field data.
Enter the flow rate for one pump and choose its unit.
Enter either differential pressure, discharge and suction pressure, or total head.
Set specific gravity for the fuel being moved.
Enter pump efficiency, motor efficiency, and service factor.
Set the number of identical pumps if you want total system demand.
Press the calculate button to place results above the form.
Use the CSV or PDF buttons to export the results.

FAQs

1) What does this calculator estimate?

It estimates hydraulic horsepower, shaft horsepower, motor input horsepower, and recommended motor horsepower for fuel pumping duties commonly seen on construction sites.

2) Why is specific gravity included?

Specific gravity adjusts pressure and head relationships for the actual fuel. Lighter or heavier liquids need different power even when the flow and head look similar.

3) When should I use discharge and suction pressure?

Use that mode when both gauge readings are available. The calculator subtracts suction pressure from discharge pressure to find the true pressure rise across the pump.

4) Can I calculate from total head instead of pressure?

Yes. Choose the head mode when your design data is in feet or meters of head. The calculator converts head into equivalent pressure using specific gravity.

5) Why are pump and motor efficiency separated?

Pump efficiency covers hydraulic and mechanical losses inside the pump. Motor efficiency covers electrical or driver losses. Keeping them separate improves selection accuracy.

6) What does service factor do?

Service factor adds operating margin above calculated demand. It helps accommodate wear, startup conditions, changing duty points, and practical motor selection ranges.

7) Is the result the exact motor nameplate size?

No. It gives a recommended continuous requirement. Final motor selection should still consider available standard sizes, site voltage, startup torque, and safety rules.

8) Which units are supported?

The calculator supports gpm, L/min, m³/h, psi, kPa, bar, MPa, feet, and meters. Results are shown in both horsepower and kilowatts.