Gallons Per Square Foot
Calculate gallons per square foot for any container. Enter length, width, and depth in feet to find total gallons, volume, and gallons per sq ft with charts.
About This Calculator
Our gallons per square foot calculator helps you determine how many US gallons of liquid fit in any rectangular container based on its dimensions. Whether you are planning a fish tank, swimming pool, water storage tank, or any other liquid container, this tool gives you instant results for total gallons, gallons per square foot of base area, volume in cubic feet, and the base area itself.
The calculation follows a simple two-step formula: first, compute the volume in cubic feet by multiplying the length, width, and depth (all in feet). Second, convert cubic feet to US gallons using the conversion factor 1 cubic foot = 7.48052 US gallons. The gallons per square foot metric is derived by multiplying the container's depth by 7.48052, representing how many gallons sit above each square foot of the base.
This calculator is useful for construction professionals estimating water tank capacity, aquarists sizing fish tanks, pool installers calculating water volume, and anyone needing quick liquid volume conversions. The results also include a visual chart showing total gallons and a breakdown of volume composition.
Regional Notes
United States: US gallons (3.785 L) are the standard for liquid measurement in construction, plumbing, and aquatics. This calculator uses US gallons.
United Kingdom: UK imperial gallons (4.546 L) differ from US gallons. If you need imperial gallons, multiply your total US gallons by 0.832674.
India: India primarily uses liters and cubic meters for liquid volume. To convert results to liters, multiply US gallons by 3.78541, or multiply cubic feet by 28.3168.
Frequently Asked Questions
How many gallons are in one square foot?
There are 7.48052 gallons in one cubic foot. To find gallons per square foot, multiply the container's height in feet by 7.48052. For example, a container 2 ft deep has about 14.96 gallons per square foot.
How do you convert square feet to gallons?
To convert square feet to gallons, multiply the base area in square feet by the height in feet to get cubic feet, then multiply by 7.48052. The formula is: gallons = length × width × depth × 7.48052.
How many square feet are in a gallon?
One US gallon equals 0.133681 cubic feet. To find square feet per gallon, divide 0.133681 by the height in feet. The result is inversely proportional to the container's depth.
What is the difference between US gallons and UK gallons?
A US gallon equals 3.785 liters (231 cubic inches), while a UK imperial gallon equals 4.546 liters (277.42 cubic inches). Our calculator uses US gallons by default, which is the standard for most construction and liquid volume applications in North America.
How many gallons of water are in a 10×10 ft tank that is 4 ft deep?
A 10×10 ft tank that is 4 ft deep has a volume of 400 cubic feet (10 × 10 × 4). Multiply by 7.48052 to get 2,992.21 US gallons. The gallons per square foot would be 29.92 (4 ft × 7.48052).
Can this calculator be used for paint coverage?
This calculator is designed for liquid volume in containers like tanks, pools, and aquariums. For paint coverage, use a dedicated paint calculator that accounts for paint type, surface porosity, number of coats, and coverage rate per gallon.
What units should I use for depth?
Depth or height must be entered in feet. If your measurement is in inches, divide by 12 first. For example, 6 inches = 0.5 ft. The calculator automatically uses feet for all dimension inputs.