A fifth is a unit of volume formerly used for wine and distilled beverages in the United States, equal to one fifth of a US liquid gallon, or 25+3⁄5 U.S. fluid ounces (757 milliliters); it has been superseded by the metric bottle size of 750 mL,[1] sometimes called a metric fifth, which is the standard capacity of wine bottles worldwide and is approximately 1% smaller.