What Is “One Drink”? Are All Drinks the Same?

What Is One Drink?

To answer this question, you need to know two things: 

  • “size” of the drink (in ounces), and 
  • amount of alcohol in the drink (alcohol by volume, or ABV).

Most standard definitions of a drink contend a “drink” equals:

  • 12oz beer that is 5% ABV
  • 5 oz of wine at 12% ABV
  • 1.5oz of liquor, such as whiskey, vodka or run, that is 40% ABV  

Typically, the amount of alcohol in liquor is presented as “proof.”  An 80-proof liquor is 40% ABV (the most common strength of whiskey and other liquors). To determine ABV for liquor, simply divide the proof in half (90-proof÷2).

Below are the standard drink sizes and their respective ABV. Multiplying the size of the drink by the percentage of alcohol by volume demonstrates why these sizes all equate to a similar amount of alcohol across beverage type. 

12 oz Beer

1.5oz 80 proof Whiskey

5oz of Wine

x .05

x .40

x .12

0.6 oz of alcohol

0.6 oz of alcohol

0.6 oz of alcohol

While this sounds simple enough, the reality is that ABV can vary widely across the same beverage type. 

  • The ABV for beer can range from as low as 3% to as high as 14%.  
  • Beers like Miller Lite and Bud Light usually fall between 4-5% ABV.
  • Many craft beers range from 6-8% ABV, with some falling between 12-14%.  

Thus, it is possible a 12 oz. beer could actually represent two or more standard drinks! Similarly, ABV varies among wines and across liquor types, too.  

In addition to variations in ABV, the amount of beverage “free poured” by bartenders can greatly deviate from the ounces attributed to standard drink sizes. For instance, wine and mixed drinks have been found to have nearly 1.5 times the alcohol of a standard drink. College students have been found to markedly overestimate the amount of fluid alcohol that should be poured to create a standard beer or mixed drink.

It is important you know “one drink” can contain drastically different quantities of alcohol depending on a variety of factors (i.e., type of alcohol, strength of alcohol, size).