Gallon (US) to Fluid ounce Conversion Calculator: Free Online Tool
Convert US gallons to fluid ounces with our free online volume converter.
Gallon (US) to Fluid ounce Calculator
How to Use the Calculator:
- Enter the value you want to convert in the 'From' field (Gallon (US)).
- The converted value in Fluid ounce will appear automatically in the 'To' field.
- Use the dropdown menus to select different units within the Volume category.
- Click the swap button (⇌) to reverse the conversion direction.
How to Convert Gallon (US) to Fluid ounce
Converting Gallon (US) to Fluid ounce involves multiplying the value by a specific conversion factor, as shown in the formula below.
Formula:
1 Gallon (US) = 128 fluid ouncesExample Calculation:
Convert 10 US gallons: 10 × 128 = 1280 fluid ounces
Disclaimer: For Reference Only
These conversion results are provided for informational purposes only. While we strive for accuracy, we make no guarantees regarding the precision of these results, especially for conversions involving extremely large or small numbers which may be subject to the inherent limitations of standard computer floating-point arithmetic.
Not for professional use. Results should be verified before use in any critical application. View our Terms of Service for more information.
What is a Gallon (US) and a Fluid ounce?
The US liquid gallon (symbol gal US) is a unit of volume in the United States customary units system. It is legally defined as 231 cubic inches, which is exactly equal to 3.785411784 liters. It is commonly used for measuring larger quantities of liquids, such as gasoline, milk, and paint.
The fluid ounce is a unit of volume. The US fluid ounce is defined as 1/128 of a US gallon (approx. 29.57 ml). The Imperial fluid ounce is 1/160 of an Imperial gallon (approx. 28.41 ml).
Note: The Gallon (US) is part of the imperial/US customary system, primarily used in the US, UK, and Canada for everyday measurements. The Fluid ounce belongs to the imperial/US customary system.
History of the Gallon (US) and Fluid ounce
The gallon has ancient roots, evolving from various Roman and medieval units. The US liquid gallon is based on the wine gallon, which was standardized in England during the reign of Queen Anne in 1707 as 231 cubic inches. This definition was adopted by the United States. It differs from the Imperial gallon used in the UK and Canada.
Derived from the ounce unit of weight/mass, adapted to measure the volume of liquids like wine or water.
Common Uses for US gallons and fluid ounces
Explore the typical applications for both Gallon (US) (imperial/US) and Fluid ounce (imperial/US) to understand their common contexts.
Common Uses for US gallons
- US Fuel: Measuring fuel (gasoline, diesel) in the United States.
- US Beverages: Selling milk and other beverages in large containers in the US.
- Household Liquids: Measuring paint and other household liquids.
- Pools & Water: Pool capacity and water usage measurements in the US.
- Industry: Some industrial applications.
Common Uses for fluid ounces
- Beverages: Measuring alcoholic drinks, soft drinks, and coffee servings.
- Cooking: Recipe measurements for smaller liquid ingredients.
- Medicine: Liquid medication dosages on prescription labels.
- Personal Care: Volumes of cosmetics, perfumes, and essential oils.
- Nutrition Labels: Serving sizes on food and beverage packaging.
Frequently Asked Questions
Questions About Gallon (US) (gal)
Is a US gallon the same as an Imperial gallon?
No. The US gallon (≈ 3.785 L) is smaller than the Imperial gallon (≈ 4.546 L). Always specify which gallon is being used if there's ambiguity.
How many quarts are in a US gallon?
There are exactly 4 US liquid quarts in 1 US liquid gallon.
How many liters are in a US gallon?
1 US liquid gallon is exactly 3.785411784 liters.
About Fluid ounce (fl oz)
Is a US fluid ounce the same as a UK fluid ounce?
No, the Imperial (UK) fluid ounce is slightly smaller than the US fluid ounce (approximately 28.41 ml vs 29.57 ml).
Is a fluid ounce the same as a weight ounce?
No, a fluid ounce measures volume (the space something occupies), while a weight ounce (specifically an avoirdupois ounce) measures mass (how much matter it contains). The relationship between the two depends entirely on the density of the substance being measured. For water, 1 US fluid ounce weighs approximately 1.04 avoirdupois ounces.
Conversion Table: Gallon (US) to Fluid ounce
| Gallon (US) (gal) | Fluid ounce (fl oz) |
|---|---|
| 1 | 128 |
| 5 | 640 |
| 10 | 1,280 |
| 25 | 3,200 |
| 50 | 6,400 |
| 100 | 12,800 |
| 500 | 64,000 |
| 1,000 | 127,999.999 |