This calculator estimates pump power requirements. Hydraulic power (power given to the fluid) is calculated by multiplying fluid density, gravity, volumetric flow rate, and total head, then dividing by 1000 (for kW). Pump power (Brake Horsepower) accounts for inefficiency and is the hydraulic power divided by pump efficiency. Motor power further accounts for motor inefficiency (assumed 95%) and is the pump power divided by motor efficiency.