In the United States, if liquor is defined as 80 proof, what is the percentage of alcohol by volume?
Alcohol by volume For example, 40% abv is 80 proof in the US and 70 proof in the UK. However, since 1980, alcohol proof in the UK has been replaced by abv as a measure of alcohol content. In the United States, a few states regulate and tax alcoholic beverages according to alcohol by weight (ABW), expressed as a percentage of total mass. Some brewers print the ABW (rather than the ABV) on beer containers, particularly on low-point versions of popular domestic beer brands. One can use the following equation to convert between ABV and ABW: At relatively low ABV, the alcohol percentage
Alcohol proof by volume. The Code of Federal Regulations (27 CFR [4-1-03 Edition] §5.37 Alcohol content) requires that liquor labels must state the percentage of ABV. The regulation permits, but does not require, a statement of the proof provided that it is printed close to the ABV number. For bottled spirits over 100 mL containing no solids, actual alcohol content is allowed to vary within 0.15% of ABV stated on the label. Alcohol proof in the United States is defined as twice the percentage of alcohol by volume. Consequently, 100-proof whiskey contains 50% alcohol by volume; 86-proof whiskey contains 43% alcohol. In