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Gallons per Square Foot Calculator

Gallons per Square Foot Scheme

1. What is Gallons per Square Foot Calculator?

Definition: This calculator determines the volume of a cuboid with a given base area and height, and calculates the volume per square foot of area in various units, including US gallons, UK gallons, and other volumetric units per square foot.

Purpose: It helps users estimate the volume of liquid over a specific area to a given height, such as in rainfall calculations, tank filling, or irrigation planning, with flexible unit conversions.

2. How Does the Calculator Work?

The calculator uses the following equations to compute the volume and volume per square foot:

  • Volume: \( V = A \times H \)
  • Volume per Square Foot: \( \text{Vol/ft}^2 = \frac{V}{A} = H \)

Where:

  • \( V \): Volume (in cubic feet or other units);
  • \( A \): Base area (in square feet or other units);
  • \( H \): Height (in feet or other units);
  • Conversion factors for volume per square foot units:
    • 1 ft³ = 0.0283168 m³;
    • 1 ft³ = 1728 in³;
    • 1 ft³ = 1 ft³;
    • 1 ft³ = 1/27 yd³;
    • 1 ft³ = 28316.8 ml;
    • 1 ft³ = 2831.68 cl;
    • 1 ft³ = 28.3168 liters;
    • 1 ft³ = 7.48052 US gallons;
    • 1 ft³ = 6.22884 UK gallons.

Steps:

  • Enter the area (\( A \)) of the surface and its unit (square feet, square inches, square yards, square meters, square centimeters, or square millimeters).
  • Enter the height (\( H \)) of the liquid layer and its unit (feet, inches, yards, meters, centimeters, or millimeters).
  • Convert the area to square feet and height to feet.
  • Calculate the volume in cubic feet: \( V = A \times H \).
  • Convert the volume to the selected unit (cubic feet, cubic yards, cubic meters, cubic inches, cubic centimeters, cubic millimeters, US gallons, or UK gallons).
  • Calculate the volume per square foot in the selected unit based on the height in feet.
  • Display results, formatted in scientific notation if the absolute value is less than 0.001, otherwise with 4 decimal places.

3. Importance of Gallons per Square Foot Calculation

Calculating volume per square foot is essential for:

  • Rainfall Estimation: Determining how much water accumulates over an area during rainfall based on the depth of water, in various units.
  • Irrigation Planning: Estimating the amount of water needed to irrigate a specific area to a certain depth, with flexible unit conversions.
  • Tank or Container Filling: Calculating the volume of liquid required to fill a container with a known base area to a specific height.

4. Using the Calculator

Example 1 (Rainfall Over a Patio): Calculate the volume and volume per square foot for rainfall over a patio:

  • Area: 200 ft²;
  • Height: 1 in;
  • Convert height: \( 1 \, \text{in} = 1 / 12 \approx 0.0833 \, \text{ft} \);
  • Volume in cubic feet: \( V = 200 \times 0.0833 \approx 16.6667 \, \text{ft}^3 \);
  • Volume in US gallons: \( 16.6667 \times 7.48052 \approx 124.6753 \, \text{US gal} \);
  • Volume per square foot (US gal/sq.ft): \( 0.0833 \times 7.48052 \approx 0.6232 \, \text{US gal/sq.ft} \);
  • Volume per square foot (l/sq.ft): \( 0.0833 \times 28.3168 \approx 2.3588 \, \text{l/sq.ft} \);
  • Result: \( V = 124.6753 \, \text{US gal} \), Volume per Square Foot = 0.6232 US gal/sq.ft or 2.3588 l/sq.ft.

Example 2 (Irrigation for a Garden): Calculate the volume and volume per square foot for irrigating a garden:

  • Area: 50 m²;
  • Height: 5 cm;
  • Convert area: \( 50 \, \text{m}^2 \times 10.7639 \approx 538.195 \, \text{ft}^2 \);
  • Convert height: \( 5 \, \text{cm} \div 30.48 \approx 0.1640 \, \text{ft} \);
  • Volume in cubic feet: \( V = 538.195 \times 0.1640 \approx 88.2640 \, \text{ft}^3 \);
  • Volume in UK gallons: \( 88.2640 \times 6.22884 \approx 549.6583 \, \text{UK gal} \);
  • Volume per square foot (UK gal/sq.ft): \( 0.1640 \times 6.22884 \approx 1.0215 \, \text{UK gal/sq.ft} \);
  • Volume per square foot (m³/sq.ft): \( 0.1640 \times 0.0283168 \approx 0.0046 \, \text{m}^3/\text{sq.ft} \);
  • Result: \( V = 549.6583 \, \text{UK gal} \), Volume per Square Foot = 1.0215 UK gal/sq.ft or 0.0046 m³/sq.ft.

5. Frequently Asked Questions (FAQ)

Q: What does volume per square foot mean?
A: It represents the volume of liquid that would cover one square foot of area to a given height, expressed in various units like US gallons, UK gallons, liters, or cubic meters per square foot.

Q: What is the difference between US gallons and UK gallons?
A: A US gallon is 231 cubic inches (approximately 3.785 liters), while a UK gallon is 277.4194 cubic inches (approximately 4.546 liters). Thus, 1 ft³ = 7.48052 US gallons or 6.22884 UK gallons.

Q: Why are there so many unit options for volume per square foot?
A: Different units are useful depending on the context—liters or milliliters for small-scale applications, cubic meters for scientific calculations, or gallons for practical uses like irrigation or rainfall estimation.

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