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⚡ Pump Water Horsepower & Electrical Cost Calculator

Calculate WHP, BHP, Motor HP, Wire-to-Water efficiency, and 24-hour electrical pumping costs.
GPM
Feet
%
%
$/kWh
Motor Horsepower & Operating Cost
60.25 Motor HP
Water HP: 45.45 | Brake HP: 55.43 | 24-hr Power: $151.03 / day
📝 Horsepower Progression Steps
Water HP = Flow (GPM) × TDH (ft)3,960

Why is the Constant 3,960 Used?

One mechanical horsepower equals 33,000 ft-lbs/min. Since 1 gallon of water weighs 8.34 lbs, the flow in lbs/min is: GPM × 8.34.

Constant = 33,000 ft-lbs/min ÷ 8.34 lbs/gal = 3,956.83 (rounded to 3,960 for standard engineering exams)

📘 Theory & Exam Guide

Learn WHP, BHP, MHP calculations, affinity laws, and electrical power costs.

Read Pumps, Power & Wire-to-Water Guide →

⚡ Power Constants

  • 1 HP0.746 kW
  • 1 kW1.341 HP
  • WHP Constant3,960
  • 1 HP33,000 ft-lb/min

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