US liquid gallon to US fluid ounce
Convert US liquid gallon (US gal) to US fluid ounce (US fl oz). Use an editable volume converter, conversion formula, and reference table.
1 US gal = 128 US fl oz
Conversion formula
One US liquid gallon equals 128 US fluid ounce. Multiply your value in US liquid gallon by this factor to get US fluid ounce. For the reverse conversion, divide by the same factor.
Worked example
To convert 5 US liquid gallon:5 × 128 = 640 US fl oz
Conversion table
| US liquid gallon (US gal) | US fluid ounce (US fl oz) |
|---|---|
| 0.01 | 1.28 |
| 0.1 | 12.8 |
| 1 | 128 |
| 2 | 256 |
| 5 | 640 |
| 10 | 1,280 |
| 25 | 3,200 |
| 50 | 6,400 |
| 100 | 12,800 |
| 1000 | 128,000 |
About these measurements
Volume describes three-dimensional space or liquid capacity.
The base reference used here is the liter. One US liquid gallon is 3.785411784 base units; one US fluid ounce is 0.02957352956 base units.
Important distinctions
US liquid measures and Imperial measures are different. Dry gallons and recipe cups are excluded.
Precision
The converter uses stored conversion factors and floating-point arithmetic. Results display up to ten significant digits, switching to scientific notation for very small or large values. Keep the precision of your original measurement when reporting results.
Common questions
How do I convert US gal to US fl oz?
Multiply the quantity in US gal by 128. You can also type the value into the converter above.
Can I reverse the conversion?
Yes. Use the swap button or open the US fluid ounce to US liquid gallon converter.
Reference
NIST Guide to the SI — conversion factors and prefix conventions. SI prefixes scale units by powers of ten; the dimension-specific notes above describe the assumptions used on this page.
