Gallon Calculator
Find liquid gallons from dimensions.
Find the liquid volume of a rectangular container in gallons.
How the Math Works
The Gallon Calculator uses a straightforward volume conversion formula: gallons = L × W × H × 7.48052. First, you multiply the length, width, and height measurements (in inches) to calculate the volume in cubic inches. Then, you multiply by the conversion factor 7.48052, which represents how many gallons are in one cubic foot (since 1 cubic foot = 1728 cubic inches and 1 cubic foot = 7.48052 gallons). This mathematical approach transforms three-dimensional space measurements into a practical liquid volume measurement.
Practical Applications
To use this calculator practically, first measure any rectangular container's interior dimensions - length, width, and height - in inches using a tape measure. Enter these values into the calculator and press calculate. For irregularly shaped containers, find the closest rectangular approximation or break the shape into smaller rectangular sections, calculate each volume separately, then sum the results. This method works for fish tanks, storage bins, concrete mixers, chemical containers, and any rectangular prism-shaped vessel where you need to know liquid capacity.
Day-to-Day Use
This calculation proves valuable in everyday situations like determining how much water a fish tank holds before adding fish, calculating the exact amount of concrete needed for a DIY project to avoid costly over-ordering, or figuring out how much pesticide solution a spray tank can carry. Homeowners use it when sizing up hot tubs, above-ground pools, or rain collection barrels. It also helps with proper chemical mixing ratios, ensuring you don't under or over-dilute solutions for cleaning, gardening, or automotive applications, ultimately saving time and money on your next project.
Worked example
2×2×1 ft → ~29.9 gal.
FAQ
Not water?
It's the volume — the weight depends on the liquid's density.