Ever wondered how much alcohol is in the cocktail you just made, or drank? Use this simple formula to calculate cocktail proof. 

alcohol content × liquor volume  ⁄  total drink volume × 100= 

% of alcohol by volume or cocktail proof

The measurements needed:

  1. Alcohol content and volume of each liquor used. In order to calculate cocktail proof, or percent of alcohol by volume, you need to know the alcohol content by volume as well as how much of each liquor was used. This tells you the volume of alcohol you’re adding per liquor.
  2. Total drink volume. The total volume of the cocktail, including alcohol, mixers and melted ice if used, is also necessary so be sure to measure the volume after shaking but before drinking!

A few things to know:

  • The alcohol volume can be found on the liquor bottle label. If you are using the proof, divide it by 2 to get the % of alcohol by volume. For example, 80 proof is 40% alcohol by volume.
  • After you know the alcohol volume, move the decimal two places to the left before using the equation. So 40% will be .4 when doing the calculation.
  • If you’re using a few different types liquors in your drink, remember to add the alcohol content contributed by each before dividing by the total drink volume.

Let’s use a margarita for example:

  • 1.5 oz silver tequila (70 proof, 35% abv)
  • 1 oz triple sec orange liqueur (80 proof, 40% abv)
  • 0.5 oz freshly squeezed lime juice
  • Ice (0.5 oz melted)

[(.35 × 1.5) + (.40 × 1)]  ⁄  (1.5 + 1 + 0.5 + 0.5)] × 100

[( .525 + .40 ) /  3.5] × 100

[.925 / 3.5] × 100

.26 × 100 =

26% ABV or 32 proof

And there you have it! Now you’ll never wonder how much alcohol was in that last cocktail, or 5.