This converter turns US gallons into cubic feet instantly, using the exact factor 1 US gallon = 0.1336805556 cubic feet. Type any number and the result updates as you go — nothing is sent to a server, so the arithmetic happens entirely in your browser.
Exactly 231 cubic inches — the US liquid gallon used for fuel and milk. The volume of a one-foot cube — used for shipping, refrigerators and natural gas.
Because the relationship is a simple proportion, one multiplication does the whole job. The table further down gives pre-computed values for the amounts people look up most often, and the result panel also reports the reverse conversion so you can check the figure both ways.
The formula
US gallons- The amount you are converting, measured in US gallons
0.1336805556- The exact number of cubic feet in one US gallon
cubic feet- The converted result
How it works, step by step
- Enter the number of US gallons you want to convert.
- The value is multiplied by 0.1336805556, the exact conversion factor.
- The result is displayed in cubic feet, rounded for readability.
- The unrounded value and the reverse conversion appear underneath so you can verify it.
Worked examples
Converting 5 US gallons
Multiply 5 by 0.13368056. That gives 0.668403 cubic feet. A quick sanity check: one US gallon is smaller than one cubic foot, so the number should get smaller — and it does.
Converting 72 US gallons
72 × 0.13368056 = 9.625 cubic feet. Working backwards, 9.625 ÷ 0.13368056 returns 72 US gallons, which confirms the factor is applied the right way round.
How to read your score
Frequently asked questions
How many cubic feet are in one US gallon?
Exactly 0.1336805556. Every conversion on this page is that single number multiplied by your input, so the result carries no rounding error beyond what is shown.
What is the formula to convert US gallons to cubic feet?
Cubic Feet = US gallons × 0.1336805556. To reverse it, divide instead: US gallons = cubic feet ÷ 0.1336805556, which is the same as multiplying by 7.480519481.
Is the US gallon bigger than the cubic foot?
No. One US gallon is only 0.133681 of a cubic foot, so the cubic foot is the larger unit.
Why does my answer differ slightly from other us-gallons to cubic-feet converters?
Most differences come from rounding the factor too early. This tool keeps full double precision through the calculation and only rounds at the final display step, and it also shows the unrounded value so you can see exactly where any difference appears.
What is a US gallon?
Exactly 231 cubic inches — the US liquid gallon used for fuel and milk.
What is a cubic foot?
The volume of a one-foot cube — used for shipping, refrigerators and natural gas.
Us Gallons to cubic feet reference table
| Us Gallons | Cubic Feet |
|---|---|
| 0.5 gal | 0.06684 ft³ |
| 1 gal | 0.133681 ft³ |
| 2 gal | 0.267361 ft³ |
| 3 gal | 0.401042 ft³ |
| 5 gal | 0.668403 ft³ |
| 10 gal | 1.3368 ft³ |
| 15 gal | 2.0052 ft³ |
| 20 gal | 2.6736 ft³ |
| 25 gal | 3.342 ft³ |
| 50 gal | 6.684 ft³ |
| 75 gal | 10.026 ft³ |
| 100 gal | 13.3681 ft³ |
| 250 gal | 33.4201 ft³ |
| 500 gal | 66.8403 ft³ |
| 1000 gal | 133.6806 ft³ |
Exact factor: 1 US gallon = 0.1336805556 cubic feet. Values rounded for display.