Fluid ounce
From Wikipedia, the free encyclopedia.
A fluid ounce is a unit of volume in both the Imperial system of units and the U.S. customary units system. However, the two measures are not quite the same:
- The U.S. fluid ounce is (1/128) gallon, about 1.805 cubic inches or 29.573531 ml. This volume of water weighs about 1.04 ounces.
- The Imperial fluid ounce is (1/160) gallon or 8 fluid drams, about 1.734 cubic inches or 28.413063 ml. This volume of water weighs exactly 1 ounce under certain temperature and pressure conditions.
http://www.hmso.gov.uk/si/si1995/Uksi_19951804_en_2.htm