Gallons to Cubic Feet Converter

Divide U.S. gallons by 7.48052 to get cubic feet. Water heaters, fish tanks and fuel tanks rated in gallons convert to space requirements this way.

How to use the Gallons to Cubic Feet Converter

1. Type the number of US gallons into the US gallons field. Decimals such as 500 are fine.
2. Read the answer in Cubic feet – it updates as you type, with no button to press.
3. To convert the other way, type into Cubic feet and the US gallons are recalculated.
4. Press Copy results to copy both values with the page title, or Copy link to share this exact conversion.

This page converts only US gal ⇄ ft³. Need a different unit? Use the general volume converter, where you can choose any “from” and “to” unit.

How it works

Both units measure volume, so they are always in the same ratio: one US gallon equals 0.13368056 cubic feet. The calculator multiplies the number of US gallons you type by 0.13368056 to give cubic feet, and when you type into the cubic feet field it divides by the same factor to give US gallons. Because the ratio never changes, doubling the US gallons always doubles the cubic feet. Results are calculated at full precision and rounded only for display (up to eight decimal places, with very large or small values shown in scientific notation).

How to convert US gallons to cubic feet

1. Write down the value in US gallons, for example 1,000 US gal.
2. Multiply by the conversion factor 0.13368056 (because 1 US gallon = 0.13368056 ft³).
3. 1,000 × 0.13368056 = 133.68056 ft³.
4. To go back from cubic feet to US gallons, divide by 0.13368056 – or multiply by 7.4805195.

US gal to ft³ conversion table

What is a US gallon?

The U.S. liquid gallon is exactly 231 cubic inches, about 3.785 litres. It is used for fuel, milk, water and paint in the United States.

What is a cubic foot?

A cubic foot is a cube 1 ft on each side, about 28.32 litres or 7.48 U.S. gallons. Refrigerators, moving trucks, gas meters and lumber are measured in cubic feet in the U.S.

Quick mental conversion

For a fast estimate, multiply US gallons by about 0.13 to get cubic feet; the error is about 2.8%. Use the calculator above when you need the exact figure.

Common mistakes to avoid

Mixing u.s. and uk gallons, pints and fluid ounces, assuming a cup is always 250 ml, and treating volume and weight as interchangeable for anything except water.