US Gallons to US Fluid Ounces Converter
1 US gallon = 128 US fluid ounces
About 17% smaller than the imperial gallon used in the UK.
A unit of volume, unrelated to the ounce of mass.
1 US gallon equals 128 US fluid ounces
How to convert US gallons to US fluid ounces
Choose the named US, Imperial or metric unit before converting a recipe or container size. A US liquid gallon is 3.785411784 L; an Imperial gallon is 4.54609 L. Volume alone cannot give ingredient mass without density.
fl oz = gal × 128One US gallon is 128 US fluid ounces, so a single multiplication converts any value.
1,280 fl oz = 10 × 128About 17% smaller than the imperial gallon used in the UK.
A unit of volume, unrelated to the ounce of mass.
US gallons to US fluid ounces conversion table
Common values in US gallons, converted to US fluid ounces.
| US gallons (gal) | US fluid ounces (fl oz) |
|---|---|
| 1 | 128 |
| 2 | 256 |
| 3 | 384 |
| 4 | 512 |
| 5 | 640 |
| 10 | 1,280 |
| 20 | 2,560 |
| 25 | 3,200 |
| 50 | 6,400 |
| 100 | 12,800 |
| 250 | 32,000 |
| 500 | 64,000 |
| 1,000 | 128,000 |
About these units
US gallongal
The US liquid gallon: exactly 231 cubic inches, or 3.785411784 litres.
US fluid ouncefl oz
One 128th of a US gallon: about 29.57 mL.
Sources and precision
Table results are rounded to 8 significant digits; formula constants may be rounded to 10. Worked example answers use 6 significant digits. The converter starts at 6 significant digits and lets you change display precision. Calculations use the stored factors without intermediate rounding. Exact unit definitions do not make an input measurement more precise; conventional and measured factors follow the assumptions stated here.