Pump Head Calculation

Pump Head Calculator

Enter system data below. The page estimates total dynamic head and required power.

Flow rate

Flow unit

Friction method

Suction pipe diameter

Discharge pipe diameter

Diameter unit

Suction line length

Discharge line length

Length and elevation unit

Suction elevation

Discharge elevation

Suction pressure

Discharge pressure

Pressure unit

Minor loss coefficient, suction

Minor loss coefficient, discharge

Fluid density, kg/m³

Dynamic viscosity, cP

Pipe roughness, mm

Hazen-Williams C

Pump efficiency, %

Flow	Suction Diameter	Discharge Diameter	Suction Length	Discharge Length	Static Head	Pressure Rise	Estimated TDH
72 m³/h	150 mm	125 mm	12 m	85 m	18.0 m	180 kPa	39.30 m

Formula Used

The calculator combines elevation, pressure, velocity, and line losses into total dynamic head.

Total Dynamic Head = Static Head + Pressure Head + Velocity Head Difference + Friction Head + Minor Loss Head

Static Head = Discharge Elevation − Suction Elevation

Pressure Head = (Discharge Pressure − Suction Pressure) ÷ (Density × g)

Velocity Head Difference = (Vd² − Vs²) ÷ (2g)

Minor Loss Head = (Ks × Vs² ÷ 2g) + (Kd × Vd² ÷ 2g)

Hazen-Williams Friction = 10.67 × L × Q^1.852 ÷ (C^1.852 × d^4.8704)

Darcy-Weisbach Friction = f × (L ÷ d) × (V² ÷ 2g)

Hydraulic Power = Density × g × Q × Head

Hazen-Williams suits clean water systems. Darcy-Weisbach handles broader fluids and uses viscosity, roughness, and Reynolds number.

How to Use This Calculator

Enter the design flow rate and pick a matching flow unit.
Choose Hazen-Williams or Darcy-Weisbach for friction calculations.
Provide suction and discharge diameters and line lengths.
Enter elevations, pressures, and minor loss coefficients.
Set density, viscosity, and efficiency for realistic power estimates.
Submit the form to view total dynamic head above the calculator.
Review the chart, summary values, and export files if needed.

FAQs

1. What is pump head?

Pump head is the total energy per unit weight added by the pump. It is usually expressed as meters or feet of fluid column.

2. What is total dynamic head?

Total dynamic head combines elevation change, pressure change, velocity effects, friction losses, and fitting losses. It helps size the pump against actual system resistance.

3. When should I use Hazen-Williams?

Use Hazen-Williams for water systems where a simple, practical estimate is enough. It is common in building and site piping work.

4. When should I use Darcy-Weisbach?

Use Darcy-Weisbach when fluid viscosity, pipe roughness, or wider fluid behavior matters. It is more general and more rigorous for engineering checks.

5. Why do suction and discharge diameters matter?

Diameter changes velocity. Velocity affects friction losses and velocity head. Smaller lines usually increase resistance and raise total pump head.

6. What are minor loss coefficients?

Minor loss coefficients represent losses from bends, valves, tees, strainers, and entrances. These local losses can meaningfully raise required head.

7. Why is efficiency included?

Efficiency converts hydraulic power into estimated shaft power. This helps with motor selection and better equipment planning during construction design.

8. Is this enough for final pump selection?

This is a strong estimating tool, but final selection should also check pump curves, NPSH, operating range, material limits, and site conditions.