How to convert US gallons to US fluid ounces
One US gallon equals 128 US fluid ounces. To convert, multiply the number of US gallons by 128:
Mental-math shortcut: One US gallon is exactly 128 fluid ounces, so multiply by 128: half a gallon is 64 fl oz.
Example
Convert 1 US gallons to US fluid ounces: 1 gal × 128 = 128 fl oz.
Gallons to Fluid Ounces conversion chart
| Gallons (gal) | Fluid Ounces (fl oz) |
|---|---|
| 0.125 | 16 |
| 0.25 | 32 |
| 0.5 | 64 |
| 0.75 | 96 |
| 1 | 128 |
| 1.5 | 192 |
| 2 | 256 |
| 2.5 | 320 |
| 3 | 384 |
| 5 | 640 |
| 10 | 1,280 |
What is a US gallon?
The US gallon (gal) is 128 US fluid ounces, or exactly 3.785411784 liters. It is used for fuel, milk and paint in the United States. The imperial (UK) gallon is about 20% larger at 4.54609 liters; this converter uses the US gallon.
What is a US fluid ounce?
The US fluid ounce (fl oz) is 1/128 of a US gallon, about 29.57 milliliters. It is used for drinks, liquid ingredients and bottle sizes in the United States. The UK imperial fluid ounce is slightly smaller, about 28.41 mL.
Frequently asked questions
How many US fluid ounces is one US gallon?
One US gallon is 128 US fluid ounces.
How do I convert US gallons to US fluid ounces?
Multiply the value in US gallons by 128. For example, 1 gal × 128 = 128 fl oz.
What is 0.5 gal in US fluid ounces?
0.5 gal is 64 US fluid ounces.
How do I convert US fluid ounces to US gallons?
Multiply US fluid ounces by 0.007813 (or divide by 128).
Conversions use the internationally agreed definitions of each unit (for example, 1 inch = 2.54 cm exactly) and are rounded for display. Volume converters use US customary units unless stated otherwise.
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