1. What is the Water Flow Rate Calculator?

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

Purpose: It helps engineers, plumbers, and irrigation specialists determine water flow rates in pipes, channels, and other hydraulic systems.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Flow rate (gallons per minute, GPM)
• \( V \) — Velocity of water (feet per second, ft/s)
• \( A \) — Cross-sectional area (square feet, ft²)
• 448.83 — Conversion factor (cubic feet per second to GPM)

Explanation: The velocity multiplied by area gives flow in cubic feet per second, which is then converted to gallons per minute.

3. Importance of Flow Rate Calculation

Details: Accurate flow rate calculations are essential for proper system design, pump selection, pipe sizing, and ensuring adequate water supply.

4. Using the Calculator

Tips: Enter the water velocity in ft/s and the cross-sectional area in ft². For circular pipes, area = π × (diameter/2)².

5. Frequently Asked Questions (FAQ)

Q1: Why is the conversion factor 448.83?
A: It converts cubic feet per second to gallons per minute (1 ft³/s = 448.83 GPM).

Q2: What's a typical water velocity in pipes?
A: Residential plumbing: 4-8 ft/s, Irrigation: 5-10 ft/s, Industrial: up to 15 ft/s depending on application.

Q3: How do I calculate area for non-circular pipes?
A: For rectangular channels: width × depth. For other shapes, use appropriate geometric formulas.

Q4: Does this work for other liquids?
A: The formula is valid for water. For other liquids, multiply by specific gravity (density relative to water).

Q5: What if I know diameter instead of area?
A: First calculate area using A = π × r² (where r = diameter/2), then use this calculator.