1. What is a Water Pump Horsepower Calculator?

Definition: This calculator estimates the required horsepower for a water pump based on flow rate, total head, and pump efficiency.

Purpose: It helps engineers, plumbers, and irrigation specialists properly size pumps for various applications.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( HP \) — Pump horsepower
• \( Q \) — Flow rate (gallons per minute)
• \( H \) — Total head (feet)
• \( \eta \) — Pump efficiency (0-1)
• 8.34 — Weight of water (lbs/gallon)
• 3960 — Conversion factor (ft-lb/min per HP)

Explanation: The formula calculates the power needed to move water against gravity and system resistance.

3. Importance of Pump Horsepower Calculation

Details: Proper pump sizing ensures efficient operation, prevents motor overload, and reduces energy costs.

4. Using the Calculator

Tips: Enter the flow rate in GPM, total head in feet, and pump efficiency (default 0.85). Efficiency must be between 0 and 1.

5. Frequently Asked Questions (FAQ)

Q1: What is total head?
A: Total head is the vertical distance plus friction losses in the piping system (measured in feet).

Q2: What's a typical pump efficiency?
A: Most pumps have 50-85% efficiency, with 0.85 being a good default for modern pumps.

Q3: How do I account for motor efficiency?
A: Divide the calculated HP by motor efficiency (typically 0.9) to get required motor HP.

Q4: What's the 8.34 constant?
A: This represents the weight of one gallon of water in pounds at standard conditions.

Q5: Should I round up the HP result?
A: Yes, always select the next available pump size greater than your calculation.