Alcohol by Volume expressed as Proof

Purpose

Use this calculator for interchanging Alcohol level between ABV and Proof unit of measures

Background

In the United Kingdom, 100 alcohol proof equals 57.17% ethanol by volume. The gunpowder test is the origin of this definition of proof. In order to demonstrate to the 16th century British sailors that their rations of rum were not watered down, it was "proved" by covering it with gunpowder and igniting it. If the rum didn't burn, it contained too much water and was "under proof", while if it burned, this meant at least 57.17% ABV was present. Rum with this alcohol percentage was defined to be 100° or one hundred degrees proof.
In the United States, alcohol proof is double the percentage of alcohol in a solution. That’s when the solution is at 60 degrees Fahrenheit or 15.6 degrees Celsius. Thus, 150 proof would be 75% alcohol and 100 proof would be 50% alcohol.
ABV is a standard measure of how much of alcohol (ethanol) is contained in a given volume of an alcoholic beverage. It is expressed as a volume percent. By definition, this is the number of milliliters (mL) of pure ethanol present in 100 mL of a solution at 20°C (68°F). The ABV standard is commonly used worldwide.

REFERENCES:

• The Origin of Alcohol Proof by Jensen William (2014)- (Department of Chemistry, University of Cincinnati);
• Title 27 Alcohol, Tobacco and Firearms, Chapter 1, §5.37. Bureau of Alcohol, Tobacco and Firearms; Department of the Treasury. p. 62.
• Canadian Food Inspection Agency - Alcoholic Beverages