Work out pump sizing for water supply instantly with clear inputs, formula shown and shareable results.
Total dynamic head adds three independent requirements: the vertical lift, the friction the pipe imposes and the residual pressure needed at the outlet, converted at 2.31 feet of head per psi. Hydraulic horsepower is GPM x head / 3960, and dividing by pump efficiency gives the shaft power the motor must supply.
Total dynamic head
TDH = static lift + friction losses + residual psi x 2.307
Power
WHP = GPM x TDH / 3960; BHP = WHP / pump efficiency
TDH = static lift + friction losses + residual psi x 2.307. Total dynamic head adds three independent requirements: the vertical lift, the friction the pipe imposes and the residual pressure needed at the outlet, converted at 2.31 feet of head per psi.
It folds together the weight of water and the conversion from foot-pounds per minute to horsepower, so GPM and feet of head give horsepower directly for water at standard density.
This calculator takes 4 inputs: Design flow, Static lift, Friction and fitting losses, Residual pressure required. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.