Convert gallons to fluid ounces
Gallon (gal) to fluid ounce (fl oz). One gallon equals 128 fluid ounces.
Formula
Gallon to fluid ounce conversion table
| Gallons | Fluid ounces | Fluid ounces | Gallons |
|---|---|---|---|
| 1 gal | 128 fl oz | 1 fl oz | 0.007813 gal |
| 2 gal | 256 fl oz | 2 fl oz | 0.015625 gal |
| 3 gal | 384 fl oz | 3 fl oz | 0.023437 gal |
| 5 gal | 640 fl oz | 5 fl oz | 0.039063 gal |
| 10 gal | 1280 fl oz | 10 fl oz | 0.078125 gal |
| 20 gal | 2560 fl oz | 20 fl oz | 0.15625 gal |
| 50 gal | 6400 fl oz | 50 fl oz | 0.390625 gal |
| 100 gal | 12800 fl oz | 100 fl oz | 0.78125 gal |
| 500 gal | 64000 fl oz | 500 fl oz | 3.9063 gal |
| 1000 gal | 128000 fl oz | 1000 fl oz | 7.8125 gal |
To convert gallons to fluid ounces, multiply the number of gallons by 128. One gallon equals 128 fluid ounces, and one fluid ounce equals 0.007813 gallons, so the relationship is fixed and exact. As a worked example, 10 gal comes to 1280 fl oz. Enter your own figure in the converter above to get an instant answer, or use the swap button to flip the direction. This is a volume conversion, and like every tool on UnitGlide it runs locally in your browser with no account or upload required. The table further down shows a range of common gallon values already worked out in fluid ounces, plus the reverse fluid ounce to gallon direction, which is handy for quick reference or double-checking a result by hand.
Frequently asked questions
How many fluid ounces are in a gallon?
One gallon equals 128 fluid ounces. The ratio is constant, so you can multiply any number of gallons by 128 to get fluid ounces.
What is the formula to convert gallons to fluid ounces?
Use fluid ounces = gallons × 128. UnitGlide applies this exact formula for every value, so results stay accurate across the whole range.
How do I convert fluid ounces back to gallons?
Go the other way by using one fluid ounce equals 0.007813 gallons. You can also press the swap button in the converter above to flip the direction in one click.
Is this gallon to fluid ounce converter accurate?
Yes. It uses internationally defined SI conversion factors, as maintained by the BIPM, and all math runs in your browser so nothing is rounded away on a server. For everyday use the displayed precision is more than enough.