Calculate total dynamic head and required flow. Review horsepower, pressure, velocity, and duty estimates instantly. Download records, compare scenarios, and support better pump selection.
| Case | Flow (gpm) | Design TDH (ft) | Brake HP | Recommended Motor (hp) | Pipe Velocity (ft/s) |
|---|---|---|---|---|---|
| Residential Deep Well | 18 | 305.76 | 2.40 | 3 | 7.35 |
| Farm Supply Line | 30 | 392.70 | 4.80 | 5 | 7.84 |
| Site Transfer Duty | 45 | 493.08 | 8.62 | 10 | 8.17 |
Use the sample rows to compare your design point with a small, medium, and heavier-duty installation pattern.
Pumping Water Level = Static Water Level + Drawdown
Pressure Head = Required Pressure × 2.31
Friction Loss ≈ 10.67 × Pipe Length × Flow1.852 ÷ (C1.852 × Diameter4.87)
Base TDH = Pumping Water Level + Discharge Elevation + Pressure Head + Friction Loss
Design TDH = Base TDH × (1 + Safety Factor ÷ 100)
Hydraulic HP = Flow × Design TDH ÷ 3960
Brake HP = Hydraulic HP ÷ Efficiency
Velocity ≈ 0.4085 × Flow ÷ Diameter²
These formulas provide planning estimates. Final equipment selection should be verified using the published performance curve for the actual pump model.
Submersible well pump sizing affects water delivery, motor loading, running cost, and service life. A pump that is too small may fail to meet pressure and flow requirements. A pump that is too large may short cycle, waste power, and operate away from its best performance point.
Total dynamic head is the backbone of pump sizing. It combines lift from the water level, elevation rise to the discharge point, required pressure, and friction losses in the pipe. When these parts are underestimated, the installed pump may not deliver the expected result on site.
Start with the real demand. Estimate the flow needed for homes, irrigation points, storage tanks, livestock systems, or temporary construction water. Then determine the pumping water level. Static water level alone is not enough because wells often draw down under load.
Next, review pipe details carefully. Long pipe runs and small diameters can add large friction losses. This extra head raises the horsepower requirement and can shift the recommended motor size upward. Pipe velocity is also useful because high velocity can increase wear and reduce system efficiency.
The design TDH gives a practical selection target. Hydraulic horsepower shows the theoretical water-moving power. Brake horsepower adds the effect of efficiency and is closer to the motor demand. The recommended motor size rounds that duty to a common equipment rating for planning.
Daily volume and tank refill time help with operational review. These outputs show whether the selected flow can support expected usage patterns. Estimated running current is also useful when coordinating electrical supply and control equipment.
This calculator is designed for early planning, comparison, and documentation. It helps organize the most important sizing inputs in one place. Always finish the selection process by checking manufacturer pump curves, motor limits, and field conditions.
Total dynamic head is the full head the pump must overcome. It includes pumping water level, discharge elevation, pressure head, and friction loss in the pipe.
Drawdown shows how far the water level falls while pumping. Ignoring it can make the pump look smaller than the job actually requires.
No. It is a planning tool. The final pump model should always be matched to the manufacturer curve at the required flow and total dynamic head.
Many designers aim for moderate velocity to control friction and wear. This calculator highlights velocity so you can judge whether the selected pipe size is reasonable.
Pressure at the outlet must be converted into head. More required pressure adds head, and more head usually increases horsepower and motor size.
The safety factor adds design margin for uncertainty, seasonal changes, fittings, and practical site variation. Too much margin, however, can oversize the pump.
Yes. The method works for many water transfer duties. You only need realistic flow, head, pipe, pressure, and efficiency values for the system.
Exports help keep job records, compare scenarios, share calculations, and support review meetings with contractors, suppliers, or project stakeholders.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.