One standard drink in the United States contains about 14 grams of pure ethanol. That amount shows up in very different glass sizes depending on what you’re drinking: 12 ounces of regular beer, 5 ounces of wine, or 1.5 ounces of distilled spirits. Those three servings look nothing alike, but they deliver the same amount of alcohol to your body.
Standard Drink Sizes by Beverage
Each of these equals one drink:
- Regular beer (5% ABV): 12 fluid ounces, or one standard can or bottle
- Malt liquor (7% ABV): 8 fluid ounces
- Table wine (12% ABV): 5 fluid ounces
- Distilled spirits like vodka, rum, gin, or whiskey (80 proof / 40% ABV): 1.5 fluid ounces, or one standard shot
The key principle is simple: as alcohol concentration goes up, serving size goes down. Malt liquor is stronger than regular beer, so you need a third less liquid to hit the same amount of alcohol. Wine is stronger still, so a single drink is less than half a can of beer by volume. And a shot of liquor packs the same punch in just an ounce and a half.
Why the Container Isn’t a Reliable Guide
A 12-ounce bottle of craft beer at 10% ABV contains two standard drinks, not one. That single bottle you grab from the fridge could count double. The same logic applies to cocktails. A margarita or a Long Island iced tea can easily contain two or three shots of liquor, meaning one glass holds two or three standard drinks.
Wine pours at restaurants also complicate things. A typical restaurant glass is six ounces, which is already slightly more than one standard drink. Some places pour even more generously. At home, without measuring, most people pour wine and spirits well above the standard. An Australian study found that drinkers consistently over-poured wine, beer, and spirits compared to standard drink sizes when pouring at home, and there’s no reason to think Americans do any better.
How Your Body Processes One Drink
Your liver breaks down alcohol at a remarkably steady pace: roughly one standard drink per hour. That rate doesn’t speed up if you drink coffee, eat food, or take a cold shower. Time is the only thing that clears alcohol from your system.
This means that if you have three drinks in an hour, your body still has about two drinks’ worth of alcohol circulating when the clock strikes the next hour. Spacing drinks out, with no more than one per hour, keeps your blood alcohol level relatively stable instead of climbing.
Calories in One Standard Drink
Alcohol itself is calorie-dense, delivering about 7 calories per gram, nearly as much as fat. Here’s what one standard drink costs you:
- Regular beer (12 oz): about 153 calories
- Light beer (12 oz): about 103 calories
- Red wine (5 oz): about 125 calories
- White wine (5 oz): about 128 calories
- 80-proof spirits (1.5 oz): about 97 calories
Spirits are the lowest-calorie option per standard drink, but only when served neat or with a zero-calorie mixer. A cocktail with juice, soda, or cream can easily double or triple that number. Craft beers are on the other end of the spectrum, ranging from 170 to 350 calories per 12-ounce serving, and many of those bottles count as two drinks because of their higher alcohol content.
Moderate Drinking Guidelines
Current U.S. dietary guidelines define moderate drinking as two drinks or fewer per day for men and one drink or fewer per day for women. These limits are based on the standard drink sizes above, so getting the measurement right matters. If your nightly “glass of wine” is actually eight ounces in a large goblet, you’re closer to one and a half standard drinks than one.
Standard Drinks Vary by Country
The 14-gram standard is specific to the United States. Other countries define a “drink” or “unit” differently, with national standards ranging from 8 to 23.5 grams of ethanol worldwide. The UK uses a smaller unit of 8 grams, designed to match smaller pour sizes without needing fractions. Australia sets its standard drink at 10 grams. Canada uses 13.45 grams. If you’re reading health guidelines from another country, the recommended number of “drinks” won’t translate directly to U.S. portions.
These differences matter most when you’re comparing international research on alcohol and health. A study saying “two drinks per day” means something quite different depending on whether it was conducted in the UK or the U.S.