How many ounces are in a gallon?

128 US fluid ounces, that is 8 pints of 16 oz each or 4 quarts of 32 oz. A US gallon is 3.785 L while an imperial gallon is 4.546 L.

Why is a US gallon smaller than an imperial gallon?

The United States kept the pre-1824 wine gallon of 231 cubic inches, while Britain defined a new imperial gallon in 1824 as the volume of 10 pounds of water. The difference is about 20 %.

Why is an oil barrel 42 gallons?

The 42-gallon barrel was standardised in 19th-century Pennsylvania to fit wooden barrels comfortably on a wagon, and it stayed when the industry moved to steel tanks. One barrel of crude oil is 158.987 L.

Ounce / Pint / Gallon / Barrel Converter

Convert US fluid ounces, pints, gallons and barrels, plus litres and millilitres.

Barrel (bbl, 42 gal) Gallon (US gal) Pint (US pt) Fluid Ounce (US fl oz)

What are fluid ounces, pints, gallons and barrels?

US liquid measures are built on the gallon: 1 gallon is 4 quarts, 8 pints, 16 cups or 128 fluid ounces, and an oil barrel is 42 gallons. British imperial units are roughly 20 % larger, so a recipe written in the UK does not convert the same way as one from the US.

Conversion Reference (US)

1 barrel = 42 gal = 336 pt = 5,376 fl oz

1 gal = 8 pt = 128 fl oz = 3.785412 L

1 pt = 16 fl oz = 473.176 mL

1 fl oz = 29.5735 mL; 1 imperial gallon = 4.54609 L (about 1.2 US gal)

Conversions run through US fluid ounces: barrels x 5,376, gallons x 128, pints x 16, and 1 fl oz = 29.5735295625 mL because the US gallon is exactly 231 cubic inches.

Worked Examples

A 12 fl oz can holds 354.9 mL, and a 16.9 fl oz bottle holds 500 mL.

A 15 gallon tank takes 15 x 3.785412 = 56.78 L, which is 12.5 imperial gallons.

Limits of This Conversion

Fluid ounces measure volume, not weight: 1 fl oz of water weighs about 1.04 oz. Barrel sizes differ by trade - 42 gal for oil, 31 gal for beer, 59 gal for a US wine barrel - and the dry gallon (4.405 L) is a separate unit. Values are rounded to six decimals.

Frequently Asked Questions

How many ounces are in a gallon?: 128 US fluid ounces, that is 8 pints of 16 oz each or 4 quarts of 32 oz. A US gallon is 3.785 L while an imperial gallon is 4.546 L.
Why is a US gallon smaller than an imperial gallon?: The United States kept the pre-1824 wine gallon of 231 cubic inches, while Britain defined a new imperial gallon in 1824 as the volume of 10 pounds of water. The difference is about 20 %.
Why is an oil barrel 42 gallons?: The 42-gallon barrel was standardised in 19th-century Pennsylvania to fit wooden barrels comfortably on a wagon, and it stayed when the industry moved to steel tanks. One barrel of crude oil is 158.987 L.