Enter the flow rate in gallons per minute and the total head in feet into the calculator to determine the water horsepower (WHP).

WHP Formula

The following formula is used to calculate water horsepower.

WHP = Q*H/3960

  • Where WHP is the water horsepower (hp)
  • Q is the volumetric flow rater of the water (gpm)
  • H is the head of the water (ft)

WHP Definition

WHP is short for water horsepower. Water horsepower is defined as the amount of work per unit of time that a pump or flow of water can generate.

Example Problem

How to calculate water horsepower?

  1. First, determine the volumetric flow rate of the water.

    For this example problem, the volumetric flow rate of the water is found to be 50 gallons per minute (GPM)

  2. Next, determine the head of the water.

    In this case, there is measured to be a total of 10 ft of head.

  3. Finally, calculate the water horsepower.

    Calculate the water horsepower using the formula above:
    WHP = Q*H/3960
    WHP = 50*10/3960
    WHP = .1262 hp