What is a Standard Drink?

How Much is a Standard Drink

You should know and understand what a standard drink is for your written DMV test.

A standard drink is a unit of measurement. We use it to compare drinks with the same amount of pure alcohol, regardless of the container size or type of alcoholic beverage.

The term can indicate the alcoholic content of a serving, just as nutrient information on food items tells you how much fat, carbs, or protein there is in a serving.

It is, however, essential to understand that a standard drink does not necessarily correspond to a typical serving size.

Beer drinkers know what I am talking about: the alcohol content of a typical beer bottle can vary a lot.

Compare Pure Alcohol Content

In the United States, a standard drink contains about 0.6 fl oz. or 14 grams of pure alcohol.

14 grams of pure alcohol corresponds roughly to:

• 12 fl oz. of regular beer.
• Five fl oz. of table wine.
• 1.5 fl oz. shot of 80-proof distilled spirits.

In other words, it doesn’t matter if you drink a standard drink of beer, wine, or spirits. They all contain the same amount of pure alcohol and will affect you the same way. The alcohol will enter your bloodstream and most likely make you a poor driver.

But as you already know, a typical serving size is not always a standard drink. A 16 oz. glass of beer, as an example, is 1 1/3 standard drink. Since beers range from approximately 3.3% to more than 10% ABV, 16 oz. of beer can contain up to 2 ounces of pure alcohol (more than three standard drinks).

How to Calculate Pure Alcohol Content

You can calculate the pure alcohol mass in a serving if you know concentration, density, and volume. Pure alcohol has a density of 789 g/l (at 20°C).

Pure alcohol mass = volume x (alcohol by volume x volumetric mass density).

A bottle of 0.35 l. (12 oz.) beer with an ABV of 5.5% has 15.2 grams (0.53 oz.) of pure alcohol.

Killing the Myths

Some of the most common myths about alcohol may appear on your test (often as false choices). It is a good idea to learn them.

• It isn’t true that beer gets you less drunk. The amount of alcohol in your blood depends mainly on how much (pure) alcohol you drink, how long time you spend drinking, and your body fat.
• A cold shower, fresh air, or hot coffee will NOT sober you up. You may feel better, but only time can reduce the amount of alcohol in your blood.
• Alcohol is NOT a stimulant. It is a depressant that slows you down.

Final Note

Note that the standard sizes are sometimes slightly different in your driver’s manual.

Standard drinks also vary in size between countries. A standard drink has less alcohol in Australia but more alcohol in Japan.

Wikipedia has of list of the definitions per country.

DMV Test Questions for Your State