Milliliters to Fluid Ounces

Bottled drinks are filled in round metric sizes and then labeled in US units, which is why American shelves are full of awkward fluid ounces. A 500 mL water bottle says 16.9 FL OZ, a 330 mL can 11.2 fl oz, a 750 mL wine bottle 25.4 fl oz and a liter bottle 33.8 fl oz. Cosmetics follow the same pattern: a 50 mL perfume is labeled 1.7 fl oz and a 30 mL serum 1.0 fl oz.

The carry-on liquids rule is the best-known example. The limit is 100 mL per container, which the US Transportation Security Administration publishes as 3.4 ounces. Strictly 100 mL is 3.38 fl oz, so a bottle marked 3.4 fl oz is about 100.5 mL, a rounding nobody enforces.

The US fluid ounce is 1/128 of a US gallon, while the British imperial fluid ounce is 1/160 of an imperial gallon, exactly 28.4130625 mL. The imperial ounce is about 4% smaller, so 500 mL is 16.9 US fl oz but 17.6 imperial fl oz. UK labels are metric first, but older recipes and pub measures may still refer to imperial ounces.

This converter, like most American products, uses the US fluid ounce. If a British source gives fluid ounces, multiply by 28.41 instead of 29.57 to get milliliters.

Fluid ounces measure volume. An ounce on a food scale measures weight, and the two match only for water-like liquids: 100 mL of water is about 3.5 oz by weight, but 100 mL of olive oil is about 3.2 oz because oil is lighter. Mixing the two is the most common error when converting ingredients.

To go the other way, see fluid ounces to milliliters. Cups, tablespoons and liters are in the unit converter.