Convert Gallon (US) to Fluid Ounce (US) (2024)

Please provide values below to convert gallon (US) [gal (US)] to fluid ounce (US) [fl oz (US)], or vice versa.

Gallon (US)

Definition: A gallon is a unit of volume specifically regarding liquid capacity in both the US customary and imperial systems of measurement. The US gallon is defined as 231 cubic inches (3.785 liters). In contrast, the imperial gallon, which is used in the United Kingdom, Canada, and some Caribbean nations, is defined as 4.54609 liters. In both systems, the gallon is divided into four quarts. Quarts are then divided into two pints and pints are divided into two cups. A cup is comprised of two gills, making one gallon equal four quarts, eight pints, sixteen cups, or thirty-two gills. Further differentiating the US and the imperial gallon, a US gill is divided into four fluid ounces, while an imperial gallon is divided into five. A US fluid ounce is therefore 1/128 of a US gallon while an imperial fluid ounce is 1/160 of an imperial gallon.

History/origin: The term gallon most closely originates from "galon" in Old Northern French and developed as a system for measuring wine and beer in England, resulting in measures such as the wine gallon, ale gallon, and imperial gallon.

Current use: In the United States (US), gallons are often used for larger containers, such as half gallon tubs of ice cream or one-gallon cartons of milk. Gallons are also widely used in fuel economy expression in the US, as well as some of its territories. The imperial gallon is used even more sparingly than the US gallon, with most countries around the world using liters when referencing fuel.

Fluid ounce

Definition: A fluid ounce (symbol: fl oz) is a unit of volume in the imperial and United States customary systems of measurement. The US fluid ounce is 1/16 of a US fluid pint, and 1/128 of a US liquid gallon, which is equal to 29.57 mL. The imperial fluid ounce is 1/20 of an imperial pint, and 1/160 of an imperial gallon, which is equal to 28.4 mL.

History/origin: The fluid ounce was originally based on the volume occupied by one ounce (weight) of a given liquid such as wine or water, thus varying based on the system being used. In 1824, the imperial gallon was defined as the volume of ten pounds of water at a temperature of 16.7°C. The imperial gallon's definition was later changed to be equal to 4.54609 liters, making the imperial fluid ounce equal to exactly 28.4130625 mL.

The United States fluid ounce was initially based on the wine gallon used in England prior to 1824. After the adoption of the international inch in 1959, the US fluid ounce became equal to exactly 29.5735295625 mL.

Current use: As the name indicates, the fluid ounce is typically used as a measurement of liquid volume. It is mostly used in the United States and the United Kingdom, as one of the many measurements of volume used.

Gallon (US) to Fluid Ounce (US) Conversion Table

How to Convert Gallon (US) to Fluid Ounce (US)

1 gal (US) = 128 fl oz (US)
1 fl oz (US) = 0.0078125 gal (US)

Example: convert 15 gal (US) to fl oz (US):
15 gal (US) = 15 × 128 fl oz (US) = 1920 fl oz (US)

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