Total Dynamic Head: static lift + discharge head + friction loss + fitting loss.
Pressure to Head: head ft = PSI × 2.31 ÷ specific gravity.
Hydraulic HP: HP = GPM × TDH × specific gravity ÷ 3960.
Brake HP: brake HP = hydraulic HP ÷ pump efficiency ÷ drive efficiency.
Recommended HP: recommended HP = brake HP × service factor.
Electrical kW: electrical kW = brake HP × 0.7457 ÷ motor efficiency.
- Enter the project name and select the fuel type.
- Confirm the specific gravity. Edit it for custom fuel blends.
- Add flow rate and choose the correct flow unit.
- Select the calculation basis. Use head inputs, pressure, or the larger safety value.
- Enter static head, discharge head, friction loss, and fitting loss.
- Add pump, drive, and motor efficiency values.
- Enter service factor for construction site margin.
- Press the calculate button. Results appear above the form.
- Use CSV or PDF buttons to save the report.
| Fuel | Flow | TDH | Specific Gravity | Pump Efficiency | Approx Brake HP |
|---|---|---|---|---|---|
| Diesel | 50 GPM | 57 ft | 0.84 | 65% | 0.95 HP |
| Gasoline | 75 GPM | 80 ft | 0.74 | 62% | 1.82 HP |
| Kerosene | 100 GPM | 120 ft | 0.81 | 68% | 3.65 HP |
| Biodiesel | 150 GPM | 145 ft | 0.88 | 70% | 6.90 HP |
Why Pump Horsepower Matters
A construction fuel pump must move liquid safely, steadily, and without overloading the motor. Horsepower tells you how much power is needed at the pump shaft. It also helps you select a motor that can handle real site conditions. Fuel transfer jobs often include long hoses, temporary tanks, elevation changes, valves, filters, meters, and quick couplers. Each item adds resistance. That resistance increases total dynamic head and raises power demand.
Flow, Head, and Fuel Weight
Flow rate is the amount of fuel moved each minute. Head is the height or resistance the pump must overcome. Specific gravity adjusts the formula for fuel weight. Diesel, gasoline, kerosene, and biodiesel do not weigh the same as water. A heavier liquid needs more power at the same flow and head. This calculator includes specific gravity, so the output is more useful for fuel handling.
Efficiency and Motor Sizing
No pump changes all input power into useful liquid power. Some energy is lost through friction, turbulence, bearings, belts, couplings, and motor heat. Pump efficiency and drive efficiency convert hydraulic horsepower into brake horsepower. Motor efficiency estimates electrical demand. The service factor adds a design margin. This is important on construction sites because hose routing, filters, tank levels, and operating conditions may change during the job.
Using the Results
Use brake horsepower for shaft load review. Use the recommended motor horsepower for motor selection. Use electrical kilowatts and daily energy cost for operating estimates. The nearest standard motor size helps with practical procurement. Always compare the result with pump curves, fuel safety rules, electrical codes, hazardous area requirements, and manufacturer limits before installation.
1. What does fuel pump horsepower mean?
Fuel pump horsepower is the power needed to move fuel at a selected flow and resistance. It includes liquid weight, head, pressure, and efficiency losses.
2. Why is specific gravity included?
Specific gravity adjusts the calculation for fuel weight. Heavier fuel needs more power than lighter fuel at the same flow rate and head.
3. What is total dynamic head?
Total dynamic head is the full resistance the pump must overcome. It includes static lift, discharge elevation, pipe friction, valves, fittings, and equipment losses.
4. Should I use pressure or head?
Use head when pipe losses and elevation are known. Use pressure when a required discharge pressure is specified. Use the larger option for conservative planning.
5. What is brake horsepower?
Brake horsepower is the power required at the pump shaft. It is higher than hydraulic horsepower because the pump and drive are not perfectly efficient.
6. Why does the calculator round motor size upward?
Motors are sold in standard sizes. Rounding upward gives a practical selection and helps avoid overload during tougher site conditions.
7. Can this calculator replace pump curves?
No. It is a planning tool. Final selection should be checked against manufacturer pump curves, motor ratings, fuel compatibility, and site safety requirements.
8. Is this useful for construction fuel transfer?
Yes. It helps estimate pump size, motor power, flow capacity, and energy demand for temporary tanks, generators, equipment fueling, and transfer systems.