Your body processes roughly one standard drink per hour. More precisely, your liver lowers your blood alcohol concentration (BAC) by about 0.015% per hour, which works out to one 12-ounce beer, one 5-ounce glass of wine, or one 1.5-ounce shot of liquor. That rate is essentially fixed. You can’t speed it up, and several factors can effectively slow it down.
What Counts as One Drink
A standard drink in the United States contains 14 grams (0.6 ounces) of pure alcohol. That translates to 12 ounces of regular beer, 5 ounces of wine, or 1.5 ounces of 80-proof spirits. The container you’re drinking from rarely matches these amounts. A pint of craft beer at 8% ABV is closer to two standard drinks. A generous pour of wine at a dinner party can easily be seven or eight ounces. If you’re trying to estimate how long it will take your body to clear what you’ve consumed, the math only works if you’re counting in standard drinks, not glasses.
How Your Liver Breaks Down Alcohol
Alcohol metabolism happens in two stages, both in the liver. In the first stage, an enzyme converts alcohol into a toxic intermediate called acetaldehyde. This is the compound responsible for much of the discomfort you feel after heavy drinking: nausea, flushing, and headache. In the second stage, another enzyme rapidly converts acetaldehyde into acetate, a harmless substance your body can use for energy or excrete.
Both stages depend on enzymes that work at a relatively constant speed. Your liver can only process so much at once, which is why drinking faster than one drink per hour causes alcohol to accumulate in your bloodstream. Three drinks in an hour means roughly three hours of processing time from your last sip, not one.
Why It Takes Longer for Some People
The 0.015% per hour figure is an average. Individual rates range from about 0.01% to 0.02% per hour, and several biological factors determine where you fall on that spectrum.
Sex. Women generally reach higher BAC levels than men after the same amount of alcohol, even at the same body weight. One reason is that men produce an enzyme in the stomach lining that breaks down about 30% of alcohol before it ever reaches the bloodstream. Women’s bodies don’t activate this same enzyme, so a larger share of each drink enters circulation intact.
Body size and composition. Alcohol distributes through water in the body, so people with more body water (generally those who are larger or have more muscle mass) dilute alcohol more effectively. A 200-pound person will have a lower BAC than a 130-pound person after the same number of drinks.
Genetics. About 30% of people with East Asian ancestry carry a gene variant that produces a less effective version of the enzyme responsible for clearing acetaldehyde. This causes acetaldehyde to build up, producing intense facial flushing and nausea. The same variant also slows overall alcohol metabolism, meaning alcohol stays in the system longer and at higher concentrations. Smaller genetic differences in enzyme activity exist across all populations.
Medications. Certain prescription drugs inhibit the liver enzymes that process alcohol. Some blood pressure and heart medications, for example, can significantly slow alcohol metabolism, leading to higher and longer-lasting BAC levels from the same amount of drinking. If you take any regular medication, it’s worth knowing whether alcohol interacts with it.
How Food Changes the Timeline
Eating before you drink doesn’t change how fast your liver processes alcohol, but it dramatically affects how much alcohol reaches your blood in the first place. In fasting subjects, peak breath alcohol levels averaged about 30.5 micrograms per 100 milliliters. After a full meal, that number dropped to 21.4, roughly a 30% reduction. Food slows the rate at which alcohol empties from the stomach into the small intestine, where most absorption occurs.
The effect is substantial enough that women who drank after a meal absorbed only about 66% of the predicted alcohol dose, and men absorbed about 71%. Drinking on an empty stomach, by contrast, resulted in nearly complete absorption. This is the single most effective thing you can do to lower your peak BAC from a given number of drinks.
What Won’t Speed Things Up
Your body eliminates alcohol on a fixed schedule. Coffee, cold showers, exercise, fresh air, and water do not accelerate metabolism. Caffeine may make you feel more alert, but your BAC stays exactly the same. A cold shower might wake you up, but it has no effect on the rate your liver clears alcohol. The only thing that sobers you up is time.
How Long Alcohol Shows Up on Tests
Even after you feel sober, alcohol or its byproducts can remain detectable depending on the type of test:
- Blood: 6 to 12 hours after your last drink
- Breath: 12 to 24 hours
- Urine: 12 to 72 hours, particularly with specialized testing that detects alcohol metabolites rather than alcohol itself
- Hair: up to 90 days
Standard breath and blood tests reflect recent drinking. Urine testing has a wider window because the body produces metabolites that linger well after alcohol itself is gone. Hair testing captures a much longer history and is typically used in legal or employment contexts rather than medical ones.
Practical Math for Common Scenarios
If you have three drinks between 8 and 10 p.m., your liver needs roughly three hours from the point your BAC peaks to bring it back to zero. Since BAC continues to rise for a short time after your last drink, you’re looking at being fully clear somewhere around 1 to 2 a.m. if you stopped at 10.
A heavier night of six drinks ending at midnight could mean your BAC doesn’t reach zero until 6 to 8 a.m., depending on your body and how quickly you drank. This is why people can still blow over the legal limit the morning after a night out. At 0.015% per hour, it takes about 6.5 hours to clear a BAC of 0.10%.
The math is simple but unforgiving: count your standard drinks, note when you stopped, and allow about one hour per drink from that point. If you ate well beforehand, your peak BAC will be lower, but the processing rate stays the same.