Enter your Area and Depth, choose your Gallon Type (US or imperial), and this Gallons Per Square Foot Calculator works out your Total Gallons, Gallons per Square Foot, and total Volume — handy whenever you need to know exactly how much liquid fits a given space.
Total Gallons
--
Gallons per Square Foot
--
Volume
--
Volume
--
A gallon is a unit of volume. The US gallon equals 3.785 liters (231 cubic inches), while the UK (imperial) gallon equals 4.546 liters. The US gallon is more commonly used in the United States, while the UK gallon is used in some Commonwealth countries.
The number of gallons in one square foot depends on the depth. At 1 foot deep, one square foot contains approximately 7.48 US gallons or 6.23 UK gallons. This is calculated using the conversion that 1 cubic foot equals 7.48052 US gallons.
To calculate gallons per square foot, multiply the depth in feet by 7.48052 for US gallons or by 6.22884 for UK gallons. For example, at 2 feet deep, you would have approximately 14.96 US gallons per square foot.
For a swimming pool, multiply the area in square feet by the average depth in feet, then by 7.48 for US gallons. A typical residential pool might be 4-6 feet deep on average, requiring 30-45 gallons per square foot of surface area.
To convert from gallons per square foot to gallons per square meter, multiply by 10.764. This accounts for the fact that 1 square meter equals approximately 10.764 square feet. For example, 7.48 gallons per square foot equals about 80.5 gallons per square meter.
A US gallon is smaller than a UK gallon. One US gallon equals 3.785 liters, while one UK gallon equals 4.546 liters. This means a UK gallon is about 20% larger than a US gallon, so volume calculations will differ depending on which gallon type you use.