1. What is a GPM Calculator?

Definition: This calculator estimates the flow rate in gallons per minute (GPM) based on fluid velocity and pipe cross-sectional area.

Purpose: It helps engineers, plumbers, and fluid system designers determine the flow rate in piping systems.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Flow rate (gallons per minute)
• \( V \) — Fluid velocity (feet per second)
• \( A \) — Cross-sectional area of pipe (square feet)

Explanation: The velocity is multiplied by the pipe area to get flow rate in ft³/s, then converted to GPM (1 ft³/s = 448.831 GPM).

3. Importance of Flow Rate Calculation

Details: Proper flow rate estimation ensures adequate system performance, proper sizing of pipes and pumps, and efficient system operation.

4. Using the Calculator

Tips: Enter the fluid velocity in ft/s and pipe cross-sectional area in ft². All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: How do I find the cross-sectional area of a pipe?
A: For circular pipes: \( A = \pi \times r^2 \) where r is the radius in feet.

Q2: What's a typical fluid velocity in pipes?
A: For water, typical velocities range from 2-8 ft/s depending on application and pipe size.

Q3: Does this work for any fluid?
A: Yes, but the result will be in GPM (volume flow rate), not accounting for fluid density.

Q4: How do I convert pipe diameter to area?
A: First convert diameter to radius (divide by 2), then use \( A = \pi \times r^2 \).

Q5: What if my pipe isn't circular?
A: Use the appropriate area formula for the pipe shape (square, rectangular, etc.).