If you ever examined a bottle of alcohol you’ve probably noticed that there are two measurements of alcoholic content printed on it. One is the alcohol percentage by volume, and the other is the proof. The terms proof refers to the amount of ethanol alcohol in an alcoholic beverage.
In the United States the proof is always twice the percentage. For example, a gin that is 88 proof has 44% alcohol.
It is important to know alcohol percentages and proof to help better understand what counts as “one drink.” The amount of alcohol in the beverage is more important than the volume of liquid. The following beverages have almost the exact same amount of alcohol.