Shake Up Your Bartending Skills 2026 – Ace the ABC Practice Exam and Pour with Confidence!

To understand how proof is calculated to determine the percentage of alcohol in a beverage, it's essential to know that the proof system operates based on the alcohol content in the liquid. In the United States, proof is defined as double the percentage of alcohol by volume (ABV).

For example, if a beverage has an ABV of 40%, its proof would be 80 (since 40% x 2 = 80 proof). Therefore, to revert from proof back to the percentage of alcohol, one would divide the proof by 2. This calculation provides a straightforward way to convert between the two measurements, ensuring accurate representation of the alcohol content in beverages.