Gallon (US) to Fluid Ounce (US)Converter
Instantly convert Gallon (US) (gal) to Fluid Ounce (US) (fl oz). Free, accurate, and easy to use.
How to Convert Gallon (US) to Fluid Ounce (US)
To convert Gallon (US) (gal) to Fluid Ounce (US) (fl oz), multiply your value by 128.00006763.
Example: 5 gal × 128.00006763 = 640.00033814 fl oz
What is a Gallon (US)?
The US liquid gallon equals 128 fluid ounces, 8 pints, or approximately 3.785 liters. It is the standard unit for fuel, water, and large liquid volumes in the United States. The UK imperial gallon is larger at approximately 4.546 liters — about 20% more. The gallon difference is a common source of confusion for international recipes and fuel economy figures.
What is a Fluid Ounce (US)?
The US fluid ounce equals approximately 29.574 milliliters, or 1/128 of a US gallon. Despite sharing a name with the mass unit ounce, it measures only volume. The UK imperial fluid ounce differs, equaling 28.413 mL (1/160 of an imperial gallon). There are 8 US fluid ounces in a cup and 128 in a gallon.
Gallon (US) to Fluid Ounce (US) Conversion Table
| Gallon (US) (gal) | Fluid Ounce (US) (fl oz) |
|---|---|
| 0.001 gal | 0.12800007 fl oz |
| 0.01 gal | 1.28000068 fl oz |
| 0.1 gal | 12.80000676 fl oz |
| 0.5 gal | 64.00003381 fl oz |
| 1 gal | 128.00006763 fl oz |
| 2 gal | 256.00013526 fl oz |
| 5 gal | 640.00033814 fl oz |
| 10 gal | 1280.00067628 fl oz |
| 20 gal | 2560.00135256 fl oz |
| 50 gal | 6400.00338141 fl oz |
| 100 gal | 12800.00676281 fl oz |
| 200 gal | 25600.01352562 fl oz |
| 500 gal | 64000.03381406 fl oz |
| 1000 gal | 128000.06762811 fl oz |
| 5000 gal | 640000.33814056 fl oz |
| 10000 gal | 1280000.67628113 fl oz |
| 50000 gal | 6400003.38140565 fl oz |
| 100000 gal | 12800006.7628113 fl oz |
| 1000000 gal | 128000067.62811302 fl oz |
| 1000000000 gal | 1.2800e+11 fl oz |
Frequently Asked Questions
How do I convert Gallon (US) to Fluid Ounce (US)?
Multiply the Gallon (US) value by 128.00006763. Formula: fl oz = gal × 128.00006763. Example: 10 gal = 1280.00067628 fl oz.
How many Fluid Ounce (US) are in one Gallon (US)?
One Gallon (US) (gal) equals 128.00006763 Fluid Ounce (US) (fl oz).
How many Gallon (US) are in one Fluid Ounce (US)?
One Fluid Ounce (US) (fl oz) equals 0.0078125 Gallon (US) (gal).
What is the exact conversion factor from Gallon (US) to Fluid Ounce (US)?
The conversion factor is 128.00006763. Multiply any gal value by this number to get fl oz. For the reverse, multiply by 0.0078125.
How do I convert Fluid Ounce (US) back to Gallon (US)?
Divide by 128.00006763, or equivalently multiply by 0.0078125. Formula: gal = fl oz ÷ 128.00006763.
Is the Gallon (US)-to-Fluid Ounce (US) conversion internationally standardized?
Yes. Both units are defined by international standards (SI or the international yard/pound agreement), so the conversion factor 128.00006763 is exact and universally agreed upon.