By Zencalcy Editorial TeamLast reviewed About us
One square foot covered to a depth of one inch holds 0.6234 US gallons, because a gallon is 231 cubic inches. That single number turns any measured area and depth into a liquid quantity — useful for sealers, pond liners, coatings and flood irrigation.
How many gallons it takes to cover an area at a given depth.
Gallons = A × D × 0.6234
A is area in square feet, D is depth in inches, and 0.6234 = 144 ÷ 231 is the number of US gallons in a square-foot-inch. For a rectangular area, enter length × width as the area.
| Symbol | Meaning |
|---|---|
| A | Area covered, in square feet. |
| D | Liquid depth, in inches. |
| Gal | US gallons (3.785 litres each). |
200 × 1.5 × 0.6234 = 187.0 gallons, or about 708 litres. That water weighs roughly 1,560 lb.
Continue with the Board Foot Calculator, Cubic Yard Calculator, Size to Weight Calculator (Rectangular Box), or the Square Feet to Cubic Yards Calculator — or browse more construction converters and all construction calculators.
A square foot one inch deep is 144 cubic inches, and one US gallon is 231 cubic inches. 144 ÷ 231 = 0.6234.
Results use standard construction estimating arithmetic: volumes from measured area and depth, unit weights from published material densities, and code-referenced spans or clearances where the page names a code. Quantities are rounded up to whole saleable units and include the stated waste allowance. These tools are planning aids, not structural design, and do not replace a licensed engineer, a local code check, or a contractor's site measurement.
Reference material used to build and check this calculator:
Last reviewed: September 2026. See how we build and check every tool on the about page.
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Content updated: September 2026