📏 US gallons to US fluid ounces Converter
Convert us gallons (gal) to us fluid ounces (fl oz) instantly, with the formula, a worked example and a conversion table.
Quick answer: 1 us gallon (gal) = 128 us fluid ounces (fl oz). Formula: fl oz = gal × 128.
Updated · Free · No sign-up · Works on any device
US gallons to US fluid ounces Converter inputs
Result
US gallons to US fluid ounces conversion table
| US gallons (gal) | US fluid ounces (fl oz) |
|---|---|
| 0.1 gal | 12.8 fl oz |
| 0.5 gal | 64 fl oz |
| 1 gal | 128 fl oz |
| 2 gal | 256 fl oz |
| 3 gal | 384 fl oz |
| 5 gal | 640 fl oz |
| 10 gal | 1,280 fl oz |
| 20 gal | 2,560 fl oz |
| 25 gal | 3,200 fl oz |
| 50 gal | 6,400 fl oz |
| 100 gal | 12,800 fl oz |
| 1,000 gal | 128,000 fl oz |
Other volume conversions
gal to mLgal to Lgal to m³gal to tspgal to tbspgal to fl ozgal to cupgal to ptgal to qtgal to imp gal
How to convert us gallons to us fluid ounces
Multiply the number of us gallons by 128 to get us fluid ounces: fl oz = gal × 128.
Example: 5 gal = 640 fl oz.
The us gallon (gal) and the us fluid ounce (fl oz) are both units of volume. Need the opposite direction? Use the fl oz to gal converter.
Popular conversions
Centimeter to InchInch to CentimeterFoot to MeterMeter to FootKilometer to MileMile to KilometerKilogram to PoundPound to KilogramCelsius to FahrenheitFahrenheit to CelsiusMilliliter to US cupUS cup to MilliliterLiter to US gallonUS gallon to LiterGram to OunceOunce to GramSquare foot to Square meterAcre to HectareKilometer per hour to Mile per hourMile per hour to Kilometer per hourMegabyte to GigabytePound per square inch to Bar
Metric and imperial units
The metric system (SI) is used by almost every country and by science worldwide. Its units scale by powers of ten – 1 kilometer is 1,000 meters, 1 meter is 100 centimeters – which makes conversions inside the system easy. The imperial and US customary systems (inches, feet, pounds, gallons) are still used daily in the United States and partly in the UK.
Since 1959 the inch has been defined as exactly 2.54 centimeters and the pound as exactly 0.45359237 kilograms, so conversions between the two systems are exact. Note that a US gallon (3.785 L) and an imperial gallon (4.546 L) are different – choose the right one above.
This converter covers 10 categories and 66 units: length, weight, temperature, volume, area, speed, time, data, energy, pressure.
Frequently asked questions
How many us fluid ounces are in a us gallon?
1 us gallon = 128 us fluid ounces.
How do I convert us gallons to us fluid ounces?
Use the formula fl oz = gal × 128. For example, 5 gal = 640 fl oz.
How do I convert us fluid ounces back to us gallons?
1 us fluid ounce = 0.0078125 us gallons. Use the fl oz to gal converter linked on this page.
Are these conversions exact?
Yes – all factors use the internationally defined values (for example 1 inch = 2.54 cm exactly, 1 pound = 0.45359237 kg exactly). Results are rounded to 8 significant digits for display.