Formula
This calculator uses the standard pump head calculator formula:
Frequently Asked Questions
TDH is the total equivalent height a pump must work against. It includes static head (elevation), friction losses in pipes, and velocity head: TDH = Static Head + Friction Head + Velocity Head.
Static head is the vertical distance between the pump inlet and the highest discharge point. It represents the minimum energy the pump must provide to lift the fluid.
Friction head = (f × L × v²) / (D × 2g), where f = Darcy friction factor, L = pipe length (m), v = velocity (m/s), D = pipe diameter (m), g = 9.81 m/s².
Velocity head = v² / (2g). It represents the kinetic energy of the fluid at the outlet expressed as an equivalent head. For most systems it is small compared to static and friction head.
TDH determines the pump's duty point on its performance curve. Selecting a pump with insufficient head results in under-delivery; too much head wastes energy.
Pump head is measured in metres (m) of fluid or feet (ft) in US customary units. Pressure can be converted: 1 bar ≈ 10.2 m of water head.