A standard drink in the United States contains about 14 grams (0.6 fluid ounces) of pure alcohol. That’s the amount found in 12 ounces of regular beer, 5 ounces of wine, or 1.5 ounces of distilled spirits. The concept exists because different alcoholic beverages have wildly different strengths, and a single measuring stick makes it easier to track how much alcohol you’re actually consuming.
What Counts as One Standard Drink
The three most common examples break down like this:
- Beer: 12 fluid ounces at about 5% alcohol by volume (ABV). That’s one regular can or bottle.
- Wine: 5 fluid ounces at about 12% ABV. This is smaller than most people picture, roughly two-thirds of a typical measuring cup.
- Distilled spirits: 1.5 fluid ounces at about 40% ABV (80 proof). This is a single shot glass.
Each of these servings delivers the same 14 grams of pure alcohol to your body. Fortified wines like port or sherry fall somewhere in between, with a standard drink being 3 to 4 ounces because of their higher alcohol content.
Why Your Actual Pour Is Probably More
The standard drink is a measurement tool, not a reflection of how drinks are typically served. A pint of beer at a bar is 16 ounces, which is 1.3 standard drinks. A generous home pour of wine can easily hit 7 or 8 ounces, pushing it past 1.5 standard drinks. Cocktails often contain more than one shot of liquor, and some use spirits well above 40% ABV.
Restaurant wine pours do tend to hover around the 5-ounce mark, which lines up neatly with one standard drink. But craft beers regularly clock in at 7%, 9%, or even 12% ABV, meaning a single pint could contain two or more standard drinks. The label is your best friend here. Most wine and spirits bottles list the percent alcohol by volume. Many beers don’t print it on the label, so you may need to look it up online.
How to Calculate Standard Drinks in Any Container
The math is straightforward. Multiply the volume of the container (in ounces) by the ABV percentage (as a decimal), then divide by 0.6. That gives you the number of standard drinks.
For example, a 25-ounce bottle of wine at 13.5% ABV: 25 × 0.135 = 3.375, divided by 0.6 = about 5.6 standard drinks. A 750 mL bottle of wine, in other words, holds more than five standard drinks, not the three or four glasses many people assume. A 16-ounce craft IPA at 7.5% ABV works out to 2 standard drinks in a single glass. The NIAAA also offers a free online drink size calculator if you’d rather skip the arithmetic.
Moderate Drinking Guidelines
The Dietary Guidelines for Americans define moderate drinking as two drinks or fewer per day for men and one drink or fewer per day for women. These limits are built on the standard drink as the unit of measurement, which is why understanding serving sizes matters. If your nightly glass of wine is actually 8 ounces, you’re consuming 1.6 standard drinks, not one.
Binge drinking is defined as reaching a blood alcohol concentration of 0.08%, which for most adults means roughly five or more drinks for men, or four or more drinks for women, within about two hours.
How Fast Your Body Processes One Drink
Your liver breaks down alcohol at a relatively fixed pace: about 7 grams per hour for an average-sized person, which works out to roughly one standard drink per hour. That rate doesn’t speed up with coffee, cold showers, or food after the fact. If you drink three standard drinks in an hour, it will take your body approximately three hours to fully process the alcohol.
That said, there’s a three- to four-fold range in how quickly different people metabolize alcohol. Women tend to process it slightly faster per unit of body weight, though they generally reach higher blood alcohol levels from the same amount because of differences in body composition. Whether you’ve eaten recently matters too. Your liver works faster in a fed state than on an empty stomach, partly because having food increases blood flow to the liver and provides the chemical building blocks that help clear alcohol more efficiently. Age, genetics, medications, and how frequently someone drinks all shift the rate as well.
Standard Drinks Vary by Country
The 14-gram definition is specific to the United States. Globally, a “standard drink” ranges from 8 to 20 grams of pure alcohol depending on where you are. In the United Kingdom and Iceland, a standard drink contains just 8 grams, roughly half the American measure. Austria defines theirs at 20 grams. Australia uses 10 grams, and Canada uses about 13.45 grams.
This means that drinking guidelines from different countries aren’t directly comparable. The UK’s recommendation of 14 “units” per week sounds similar to the U.S. framework, but each UK unit is much smaller, so the actual alcohol limit is different. If you’re reading health information from another country, check what their standard drink size is before applying their guidelines to your own habits.