This converter turns US fluid ounces into US gallons instantly, using the exact factor 1 US fluid ounce = 0.0078125 US gallons. Type any number and the result updates as you go — nothing is sent to a server, so the arithmetic happens entirely in your browser.
One eighth of a US cup, roughly 29.57 millilitres. Exactly 231 cubic inches — the US liquid gallon used for fuel and milk.
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 fluid ounces- The amount you are converting, measured in US fluid ounces
0.0078125- The exact number of US gallons in one US fluid ounce
US gallons- The converted result
How it works, step by step
- Enter the number of US fluid ounces you want to convert.
- The value is multiplied by 0.0078125, the exact conversion factor.
- The result is displayed in US gallons, rounded for readability.
- The unrounded value and the reverse conversion appear underneath so you can verify it.
Worked examples
Converting 5 US fluid ounces
Multiply 5 by 0.0078125. That gives 0.039062 US gallons. A quick sanity check: one US fluid ounce is smaller than one US gallon, so the number should get smaller — and it does.
Converting 72 US fluid ounces
72 × 0.0078125 = 0.5625 US gallons. Working backwards, 0.5625 ÷ 0.0078125 returns 72 US fluid ounces, which confirms the factor is applied the right way round.
How to read your score
Frequently asked questions
How many US gallons are in one US fluid ounce?
Exactly 0.0078125. 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 fluid ounces to US gallons?
Us Gallons = US fluid ounces × 0.0078125. To reverse it, divide instead: US fluid ounces = US gallons ÷ 0.0078125, which is the same as multiplying by 128.
Is the US fluid ounce bigger than the US gallon?
No. One US fluid ounce is only 0.0078125 of a US gallon, so the US gallon is the larger unit.
Why does my answer differ slightly from other us-fluid-ounces to us-gallons 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 fluid ounce?
One eighth of a US cup, roughly 29.57 millilitres.
What is a US gallon?
Exactly 231 cubic inches — the US liquid gallon used for fuel and milk.
Us Fluid Ounces to US gallons reference table
| Us Fluid Ounces | Us Gallons |
|---|---|
| 0.5 fl oz | 0.003906 gal |
| 1 fl oz | 0.007812 gal |
| 2 fl oz | 0.015625 gal |
| 3 fl oz | 0.023438 gal |
| 5 fl oz | 0.039062 gal |
| 10 fl oz | 0.078125 gal |
| 15 fl oz | 0.117188 gal |
| 20 fl oz | 0.15625 gal |
| 25 fl oz | 0.195312 gal |
| 50 fl oz | 0.390625 gal |
| 75 fl oz | 0.585938 gal |
| 100 fl oz | 0.78125 gal |
| 250 fl oz | 1.9531 gal |
| 500 fl oz | 3.9062 gal |
| 1000 fl oz | 7.8125 gal |
Exact factor: 1 US fluid ounce = 0.0078125 US gallons. Values rounded for display.