fl oz

US fluid ounce

Volumeexact by definition

The US fluid ounce is exactly 1/128 of a US gallon, which is 29.5735295625 mL. It is the standard unit on American beverage and food labels. The factor is exact by definition, following from the exact US gallon.

Watch out: The imperial fluid ounce is 28.4130625 mL, about 4% smaller, even though the imperial gallon is 20% larger. The gallons divide differently: 128 US fluid ounces to the US gallon but 160 imperial fluid ounces to the imperial gallon. A recipe calling for ounces from a British source is not measuring the same thing as an American one, and US nutrition labelling additionally treats a "fluid ounce" as exactly 30 mL for serving sizes.

1 fl oz 0.02957353 L