One standard drink in the United States contains 0.6 fluid ounces (14 grams) of pure alcohol. That’s the fixed amount regardless of what you’re drinking. What changes is how much liquid it takes to reach that threshold, because beer, wine, and spirits all have different alcohol concentrations.
Standard Drink Sizes by Beverage Type
The 0.6-ounce pure alcohol benchmark translates to very different pour sizes depending on what’s in your glass. For the three most common categories:
- Regular beer (5% ABV): 12 fluid ounces, or one typical can or bottle.
- Wine (12% ABV): 5 fluid ounces, which is noticeably less than most people pour at home.
- Distilled spirits (40% ABV / 80 proof): 1.5 fluid ounces, or one standard shot.
These three servings all contain exactly the same amount of alcohol. Your body processes them identically. A glass of wine isn’t “lighter” than a shot of vodka if both are poured to standard size. The difference is only in how much liquid surrounds that alcohol.
Why Your Actual Drink Is Probably More Than One
Standard drink sizes were designed as a unit of measurement, not as a reflection of how drinks are actually served. In practice, most pours exceed one standard drink, sometimes significantly.
A typical restaurant wine pour is 6 ounces, which is already 1.2 standard drinks. Many wines now clock in at 14% or 15% ABV rather than 12%, pushing that same glass closer to 1.5 standard drinks. A pint of beer at a bar is 16 ounces, not 12, so even a regular 5% beer on draft is 1.3 standard drinks. And craft beers ranging from 7% to 9% ABV in a pint glass can easily equal two standard drinks in a single serving.
Mixed cocktails are the hardest to gauge. A margarita or Long Island iced tea can contain two, three, or even four standard drinks depending on the recipe and the bartender’s hand. If you’re trying to track your intake, cocktails are where the math gets especially unreliable.
How to Calculate Standard Drinks Yourself
You can figure out the number of standard drinks in any beverage with a simple formula: multiply the volume in ounces by the ABV (as a decimal), then divide by 0.6.
For example, a 16-ounce pint of 7% IPA: 16 × 0.07 = 1.12 ounces of pure alcohol. Divide by 0.6 and you get 1.87 standard drinks. A 9-ounce pour of 14% wine: 9 × 0.14 = 1.26 ounces of pure alcohol, or 2.1 standard drinks. This math is worth doing at least once for the drinks you have most often, because the results are frequently surprising.
How Fast Your Body Processes One Drink
Your liver metabolizes alcohol at a remarkably consistent rate: roughly one standard drink per hour. This rate doesn’t speed up with coffee, food, water, or exercise. Time is the only thing that clears alcohol from your system.
This means if you have three standard drinks over the course of an hour, it will take approximately three hours from your last sip for your body to fully process all of it. And because many single servings contain more than one standard drink, a “couple of beers” that are actually craft pints could represent four or more hours of processing time. Understanding this rate is useful not just for safety behind the wheel but for gauging how you’ll feel the next morning.
Moderate Drinking Guidelines
Current U.S. dietary guidelines define moderate drinking as two standard drinks or fewer per day for men and one or fewer for women. These limits are based on standard drink units, which is precisely why knowing what counts as “one drink” matters so much. If your nightly wine glass holds 8 ounces of 14% wine, that’s nearly two standard drinks, not one.
The guidelines also note that not drinking at all is a valid choice, and that people who don’t currently drink shouldn’t start for any perceived health benefit.
Standard Drinks Vary by Country
If you encounter standard drink references from other countries, be aware the numbers differ. A Canadian standard drink contains 17.05 milliliters of pure ethanol, which works out to about 13.45 grams, slightly less than the U.S. definition. Australia sets its standard drink at 10 grams of pure alcohol, while the UK uses 8 grams (called a “unit”). This means a drink described as “two standard drinks” in an Australian health pamphlet represents less alcohol than the same label in the U.S. When reading international health advice, check which country’s definition is being used.