Fluid ounce - Definition and Overview

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 Imperial fluid ounce is (1/160) of an imperial gallon or 8 fluid drams, about 1.734 cubic inches or exactly 28.413 062 5 mL (as specified legally in The Units of Measurement Regulations 1995 (http://www.hmso.gov.uk/si/si1995/Uksi_19951804_en_2.htm)). This volume of water weighs very nearly 1 avoirdupois ounce.
• The U.S. fluid ounce is (1/128) of a U.S. fluid gallon, about 1.805 cubic inches or exactly 29.573 529 562 5 mL. This volume of water weighs about 1.04 avoirdupois ounces.

External link

Conversion Calculator for Units of VOLUME (http://www.ex.ac.uk/trol/scol/ccvol.htm)