In the United States, one standard drink contains 14 grams (0.6 fluid ounces) of pure alcohol. That’s the amount found in a 12-ounce beer at 5% alcohol, a 5-ounce glass of wine at 12% alcohol, or a 1.5-ounce shot of 80-proof spirits at 40% alcohol. But many of the drinks people actually pour, order, or buy contain more than one standard drink, which is why understanding the math matters.
What Counts as One Standard Drink
A standard drink isn’t about the type of alcohol. It’s about the total amount of pure alcohol in the glass. All three of these contain the same 14 grams:
- Beer: 12 ounces at 5% ABV
- Wine: 5 ounces at 12% ABV
- Spirits: 1.5 ounces at 40% ABV (80 proof)
The problem is that these “standard” pours rarely match what people actually drink. A typical restaurant wine pour is 6 ounces, not 5. A pint glass holds 16 ounces, not 12. And cocktails often contain more than one shot. Each of those common servings holds more than one standard drink.
How to Calculate Drinks in Any Beverage
You can figure out the number of standard drinks in any container using a simple formula: multiply the volume of the container (in ounces) by the alcohol percentage (as a decimal), then divide by 0.6. For example, a 16-ounce pint of 5% beer: 16 × 0.05 = 0.8, divided by 0.6 = 1.3 standard drinks.
This calculation becomes especially important with craft beer and high-ABV beverages. A 12-ounce craft IPA at 7.5% ABV contains about 1.5 standard drinks. A 16-ounce can of that same IPA holds roughly 2 standard drinks. A 9-ounce pour of 14% red wine is nearly 2.1 standard drinks. A single margarita made with 3 ounces of tequila contains 2 standard drinks before you even account for any added liqueur.
The NIAAA offers an online drink size calculator where you plug in the ABV and container size to get an exact count. It’s useful for bottles of wine (a standard 750ml bottle at 12% contains about 5 standard drinks) or larger beer containers.
Recommended Limits
The Dietary Guidelines for Americans set the threshold at 2 drinks or fewer per day for men and 1 drink or fewer per day for women. This is a daily cap, not a weekly average. You can’t “save up” six drinks for Saturday by abstaining Monday through Friday.
Binge drinking is defined as reaching a blood alcohol concentration of 0.08%, which typically happens when men consume 5 or more drinks, or women consume 4 or more drinks, within about two hours. By that definition, splitting a bottle of wine with a friend over a quick dinner puts many women at the binge threshold.
The World Health Organization takes a harder line, stating that no level of alcohol consumption is safe for health. Alcohol is classified as a Group 1 carcinogen (the same category as tobacco) and causes at least seven types of cancer, including breast and bowel cancer. Notably, the WHO found that half of all alcohol-related cancers in Europe were caused by “light” and “moderate” drinking, not heavy consumption. There is no identified threshold below which alcohol’s cancer risk disappears.
How Your Body Processes Each Drink
Your liver clears roughly one standard drink per hour, and nothing speeds that up. Not coffee, not food, not a cold shower. If you have three drinks between 8 and 9 p.m., your body won’t finish processing the alcohol until around midnight.
Several factors affect how quickly alcohol hits you, even if the number of standard drinks is the same. Eating before or during drinking, particularly protein and fatty foods, slows absorption by keeping alcohol in the stomach longer. Carbonated mixers do the opposite, increasing the rate your body absorbs alcohol by creating pressure that pushes it into the bloodstream faster. Drinking at high altitude can make the same number of drinks feel nearly twice as strong for the first few days.
Women generally reach higher blood alcohol levels than men from the same number of drinks, even at the same body weight. This is partly because women tend to have lower levels of the stomach enzyme that breaks down alcohol before it enters the bloodstream, along with differences in body water content that keep alcohol more concentrated.
Standard Drinks Vary by Country
If you’re reading health guidelines from outside the US, the numbers won’t line up. The United Kingdom defines a standard drink as just 8 grams of pure alcohol, nearly half the US definition. Australia uses 10 grams. So when a UK guideline recommends no more than 14 units per week, those are smaller units than what Americans call a standard drink. A direct comparison requires converting to grams of pure alcohol rather than counting “drinks” across borders.
Why Most People Undercount
Studies consistently find that people underestimate how much they drink, and the standard drink framework explains why. A “glass of wine” at home is whatever fits in the glass you grabbed, which is often 7 or 8 ounces rather than the standard 5. A cocktail with 2 or 3 ounces of spirits counts as 1.3 to 2 standard drinks, but most people log it as one drink. A 24-ounce tallboy of 8% double IPA contains 3.2 standard drinks in a single can.
If you’re trying to stay within guidelines or simply want an accurate picture of your intake, measuring once with a kitchen scale or measuring cup can be eye-opening. Most people discover their “one drink” has been closer to two all along.