Calculate the Water Horsepower (WHP) and Brake Horsepower (BHP) required for a centrifugal pump.
Last updated: March 2026 | By ForgeCalc Engineering
Pump horsepower is the power required to move a specific volume of fluid against a certain pressure (head). There are two main types: Water Horsepower (WHP) and Brake Horsepower (BHP).
Water Horsepower is the theoretical power added to the fluid.Brake Horsepower is the actual power required at the pump shaft, accounting for mechanical and hydraulic losses within the pump itself.
It is the total equivalent height that a fluid is to be pumped, taking into account friction losses in the pipe, valves, and fittings, plus the static elevation change.
Power is directly proportional to SG. Pumping a fluid twice as dense as water (SG=2.0) requires exactly twice the horsepower.
Centrifugal pumps typically operate between 60% and 85% efficiency at their Best Efficiency Point (BEP). Smaller pumps are generally less efficient.
It is derived from (33,000 ft-lb/min per HP) divided by (8.34 lbs/gal for water), which equals 3960.
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