A healthy liver processes alcohol at a roughly fixed rate, lowering your blood alcohol concentration (BAC) by about 0.015 per hour. That means a single standard drink takes about one hour to clear, and a night of heavier drinking can take far longer than most people expect. Someone who stops drinking at midnight with a BAC of 0.15 won’t hit 0.00 until about 10 a.m. the next morning.
How Your Body Processes Alcohol
Your liver does the vast majority of the work. Enzymes break alcohol down into a toxic intermediate compound, which is then quickly converted into a harmless substance your body can use for energy or excrete. This process handles roughly 0.5 fluid ounces of pure alcohol per hour, and it runs at a near-constant speed regardless of how much you drank. That fixed pace is why you can’t rush sobriety.
One standard drink contains about 14 grams of pure alcohol. That’s a 12-ounce can of regular beer (5%), a 5-ounce glass of wine (12%), or a 1.5-ounce shot of 80-proof spirits. Each one adds roughly one hour to your sobering-up timeline. But many real-world drinks exceed those sizes: a strong craft IPA, a generous restaurant pour of wine, or a mixed cocktail with two shots all count as more than one standard drink, even though they arrive in a single glass.
Estimating Your Timeline
The simplest way to estimate how long sobering up will take is to work backward from your BAC. Subtract 0.015 for each hour that passes after your last drink. A 180-pound man who has eight drinks over four hours, for example, might reach a BAC around 0.167. After four hours of metabolizing during that drinking window, his BAC would still be roughly 0.107, well above the 0.08 legal driving limit in most U.S. states. From that point, he’d need about seven more hours to reach zero.
Here are some rough benchmarks for a person starting from different BAC levels, assuming no more alcohol is consumed:
- BAC 0.08 (legal limit): approximately 5.5 hours to reach 0.00
- BAC 0.12 (moderately drunk): approximately 8 hours
- BAC 0.15 (significantly impaired): approximately 10 hours
- BAC 0.20 (very intoxicated): approximately 13 hours
These are averages. Your actual timeline could be shorter or longer depending on several biological factors.
Why Some People Sober Up Faster
Body composition matters more than most people realize. Research from the University of Illinois found that lean body mass, meaning everything in your body except fat, is one of the strongest predictors of how fast you clear alcohol. That’s because lean body mass correlates closely with the amount of functional liver tissue doing the metabolic work. Women with higher lean body mass and older age cleared alcohol up to 52% faster than younger women at a healthy weight. The average elimination rate ranged from 6 grams of alcohol per hour in the healthy-weight group to 9 grams per hour in the group with obesity, largely driven by differences in lean mass.
Biological sex also plays a role. Women generally have less of the key enzyme that begins breaking down alcohol in the stomach lining, which means more alcohol reaches the bloodstream per drink. Women also tend to have a higher body fat percentage relative to their weight, which means less water to dilute the alcohol. The net effect: women typically reach higher BAC levels than men of comparable weight after the same number of drinks.
Age slows things down in a different way. As you get older, liver function gradually declines, and the enzymes responsible for alcohol metabolism become less efficient. Certain medications can also interfere with these enzymes, further slowing clearance.
Coffee, Cold Showers, and Other Myths
Nothing speeds up the rate your liver processes alcohol. Coffee, cold showers, exercise, bread, and “sweating it out” are all persistent myths. An FDA scientific review found that caffeine had no significant effect on blood alcohol concentration, even at relatively high doses. What caffeine does is mask some of the drowsiness alcohol causes, which can actually be dangerous: you feel more alert while remaining just as impaired. This is why caffeinated alcoholic beverages drew regulatory concern. You’re not sobering up. You’re just less aware of how drunk you are.
Food can slow alcohol absorption if you eat before or while drinking, which means your BAC may peak lower. But once alcohol is in your bloodstream, food won’t help clear it any faster. Drinking water is important for staying hydrated and may ease hangover symptoms later, but it has no effect on your BAC timeline.
Sober on a Breathalyzer Doesn’t Mean Fully Recovered
One of the most underappreciated facts about sobering up: reaching a BAC of 0.00 doesn’t mean your brain is back to normal. Hangover symptoms begin precisely as BAC approaches zero, and the cognitive impairment that comes with them is real and measurable.
Studies have documented slower reaction times, more frequent errors on tasks requiring attention, and significant deficits in memory during a hangover state. One study found that hungover participants recalled roughly 30% fewer items on a memory task compared to a control group, even after accounting for factors like age, weekly drinking habits, and mood. Psychomotor performance, the coordination between what you see and how your body responds, is also diminished. This matters for driving, operating machinery, or any task where split-second judgment counts.
The practical takeaway: even after your BAC hits zero, you may not be performing at your best for several more hours. The total recovery window from a heavy night of drinking can stretch well into the next afternoon, combining the hours needed to metabolize the alcohol itself with the lingering cognitive fog of a hangover.
A Realistic Picture
If you had three or four drinks over a couple of hours at dinner, you’re probably looking at two to four hours after your last drink before your BAC returns to zero. If you had a heavier night, six to eight drinks or more, the math pushes well into the next morning. A person who stops drinking at 2 a.m. with a BAC around 0.18 won’t metabolize all of that alcohol until roughly noon, and may not feel cognitively sharp until the afternoon.
The only reliable strategy is time. Plan accordingly, especially if you need to drive the next morning. Many people are surprised to learn they can still be above the legal limit hours after their last drink, even after sleeping. Setting a personal cutoff time the night before and using a BAC calculator to estimate your timeline are the most practical tools available.