A standard serving of alcohol in the United States contains roughly 14 grams of pure ethanol. That amount looks different depending on what you’re drinking: 12 ounces of beer, 5 ounces of wine, or 1.5 ounces of distilled spirits. Each of these contains the same amount of alcohol, just in different volumes and concentrations.
Standard Drink Sizes by Beverage
The key to understanding a “standard drink” is that it’s not about the size of the glass. It’s about the alcohol inside. A light beer fills a whole bottle, while a shot of vodka barely covers the bottom of a tumbler, but both deliver the same 14 grams of pure alcohol to your body. Here’s how it breaks down:
- Regular beer (5% ABV): 12 fluid ounces, roughly one standard bottle or can.
- Malt liquor or hard seltzer (7% ABV): 8 to 10 fluid ounces, which is less than a full pint glass.
- Table wine (12% ABV): 5 fluid ounces, smaller than most people expect.
- Fortified wine like port (17% ABV): 3 to 4 fluid ounces.
- Distilled spirits like vodka, whiskey, gin, rum, or tequila (40% ABV / 80 proof): 1.5 fluid ounces, a single shot.
The ABV (alcohol by volume) percentage printed on every label tells you how much of that liquid is pure alcohol. Higher ABV means you need less liquid to reach one standard drink.
Why Your Actual Pour Is Probably More
Most people underestimate how much they’re actually drinking. A standard wine pour at a restaurant is about 5 ounces, which lines up neatly with one standard drink. But at home, without measured glassware, it’s easy to fill a large wine glass to 7 or 8 ounces without thinking twice. That single glass is now closer to 1.5 standard drinks.
Beer creates similar confusion. Many craft beers run 7% to 10% ABV or higher. A 16-ounce pint of a 9% double IPA contains nearly three standard drinks, not one. The same applies to cocktails: a margarita made with two ounces of tequila and an ounce of triple sec can easily count as two or more standard drinks in a single glass.
How to Calculate Drinks in Any Container
You can estimate the number of standard drinks in any beverage with a simple formula. Multiply the volume in ounces by the ABV as a decimal, then multiply that result by two. For example, a 16-ounce can of 6% beer: 16 × 0.06 = 0.96, then 0.96 × 2 = 1.92 standard drinks. That one tallboy is almost two drinks.
This calculation is especially useful for wine bottles and mixed drinks where the serving isn’t pre-portioned. A standard 750ml wine bottle (about 25 ounces) at 12% ABV works out to five standard drinks. Split it between two people over dinner, and each person has had 2.5 drinks.
Standard Drinks Vary by Country
The 14-gram definition is specific to the United States and Canada. Other countries set the bar differently, which matters if you’re reading health guidelines from international sources.
The UK uses 8 grams as one unit of alcohol, nearly half the American standard. Australia, France, Germany, and New Zealand all define a standard drink as 10 grams. Japan sets it at 20 grams. So when a British health campaign says “14 units per week,” that translates to about 8 American standard drinks, not 14.
What One Drink Does to Your Body
A single standard drink raises your blood alcohol concentration (BAC) by roughly 0.01% to 0.03% over the course of an hour, depending on your weight, sex, and whether you’ve eaten. Your liver processes alcohol at a fairly fixed rate, clearing about one standard drink per hour. Drinking faster than that causes alcohol to accumulate in your bloodstream.
This is why the pace of drinking matters as much as the total amount. Three drinks over four hours affects your body very differently than three drinks in one hour, even though the total alcohol is identical.
How Standard Drinks Relate to Guidelines
U.S. guidelines for moderate drinking are built around standard drink counts. The CDC defines moderate use as two drinks or fewer per day for men and one drink or fewer per day for women. The difference reflects how body composition and enzyme activity affect alcohol metabolism.
Binge drinking is defined as reaching a high blood alcohol level in a short window: four or more drinks on a single occasion for women, five or more for men. Because many cocktails and large pours contain more than one standard drink, it’s possible to hit those thresholds in just two or three glasses without realizing it. Knowing the actual standard drink count in what you’re drinking is the only reliable way to track where you stand.