US Fluid Ounces to US Gallons
Convert us fluid ounces to us gallons instantly. 1 fl oz = 0.0078125 gal. Includes the exact factor, a conversion table of common values and the definition of both units.
How to convert us fluid ounces to us gallons
To convert us fluid ounces to us gallons, divide by 128 (multiply by 0.0078125). The relationship is fixed, so the same factor works for any quantity — there is nothing to look up and nothing that changes with temperature, location or context.
gal = fl oz × 0.0078125
US Fluid Ounces to US Gallons conversion table
The values people look up most often, rounded for reading. Use the calculator above for anything in between.
| US Fluid Ounces | US Gallons |
|---|---|
| 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 |
| 20 fl oz | 0.15625 gal |
| 25 fl oz | 0.195312 gal |
| 50 fl oz | 0.390625 gal |
| 100 fl oz | 0.78125 gal |
| 500 fl oz | 3.90625 gal |
| 1,000 fl oz | 7.8125 gal |
What is a us fluid ounce?
A sixteenth of a US pint, about 29.6 mL.
What is a us gallon?
Exactly 231 cubic inches — smaller than the imperial gallon.
The formula
gal = fl oz × 0.0078125
Every result on this page comes from this formula. Nothing is rounded until the final display, so figures match a spreadsheet to the cent.
How to use the US Fluid Ounces to US Gallons
- Type the number of us fluid ounces you want to convert.
- Read the result in us gallons straight away — there is no button to press.
- Check the table below for the values that come up most often, or reverse the conversion with the linked us gallons to us fluid ounces page.
US Fluid Ounces to US Gallons — frequently asked questions
How many us gallons are in a us fluid ounce?
One us fluid ounce equals 0.0078125 gal. gal = fl oz × 0.0078125
What is the formula to convert us fluid ounces to us gallons?
The formula is gal = fl oz × 0.0078125. It is an exact definition rather than an approximation, so the conversion never drifts no matter how large the number.
How do I convert us gallons back to us fluid ounces?
Divide instead of multiplying: one us gallon is 128 fl oz. The reverse converter is linked in the related tools list.
Is this conversion exact?
Yes. Both units are defined against the same base unit by international agreement, so the factor is exact — any rounding you see is only in the display, which you can widen by entering more decimal places.
Is this us fluid ounces to us gallons free to use?
Yes. Every calculator on the site is free, needs no sign-up, and runs entirely in your browser, so your figures never leave your device.
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About this calculator
Written and reviewed by The Samsung Calculator editorial team. Every calculator is written against a published formula, reviewed against at least one independent reference implementation, and dated when it changes.
Last reviewed August 15, 2026 · Calculation runs client-side · No data collected · Report an error