Your body clears alcohol from your blood at a fairly fixed rate, typically lowering your blood alcohol concentration (BAC) by 0.010 to 0.020 per hour. That means if your BAC reaches 0.08, the legal driving limit in most U.S. states, it will take roughly 4 to 8 hours to drop back to zero. A BAC of 0.10 takes 5 to 10 hours to fully clear.
The exact timeline depends on how much you drank, how quickly you drank it, your body size and composition, and your biological sex. But one thing is consistent: your liver sets the pace, and nothing you do from the outside can speed it up.
Why Your Liver Sets a Fixed Pace
Unlike most substances your body processes, alcohol is broken down at a nearly constant rate regardless of how much is in your system. Your liver uses an enzyme that converts ethanol into a toxic intermediate compound, which a second enzyme then quickly converts into a harmless substance your body can use for energy or excrete. The first enzyme gets fully saturated even at low alcohol concentrations, so it works at maximum capacity from essentially the first drink onward. Adding more alcohol to your blood doesn’t make the process go faster. It just means the line is longer.
This is why doubling the number of drinks you had roughly doubles the time it takes to reach zero. There’s no shortcut through the bottleneck.
Estimating Your Personal Timeline
A standard drink in the United States contains about 14 grams of pure alcohol. That’s one 12-ounce beer at 5% alcohol, one 5-ounce glass of wine at 12%, or one 1.5-ounce shot of liquor at 40%. Each standard drink raises the average person’s BAC by roughly 0.02 to 0.03, though this varies significantly by body size.
Using the average elimination rate of 0.015 per hour, here’s a rough guide:
- 2 standard drinks (BAC ~0.04–0.06): about 3 to 4 hours to clear
- 4 standard drinks (BAC ~0.08–0.10): about 5 to 7 hours
- 6 standard drinks (BAC ~0.12–0.15): about 8 to 10 hours
- 8 standard drinks (BAC ~0.16–0.20): about 10 to 13 hours
These are estimates for a person of average weight. Your actual BAC depends on many individual factors, and peak BAC also depends on how quickly you consumed the drinks.
Factors That Change the Timeline
Several things influence how high your BAC gets and how long it stays elevated.
Body size and composition play a major role. Alcohol distributes through body water, not fat. A larger, more muscular person has more water volume to dilute the alcohol, resulting in a lower peak BAC from the same number of drinks. A smaller person, or someone with a higher body fat percentage, will reach a higher BAC faster.
Biological sex matters independently of body size. Women generally absorb more alcohol and take longer to process it than men, even at equivalent body weights. This is partly due to differences in body composition, hormone levels, and enzyme activity. The result is that women typically reach a higher BAC from the same amount of alcohol.
Food in your stomach significantly affects absorption. Eating before or while drinking slows the rate at which alcohol enters your bloodstream. Research published in the American Journal of Physiology found that food increased the amount of alcohol broken down before it ever reached the general circulation: about 30% of the dose was metabolized during this “first pass” when consumed with food, compared to just 4% when consumed with water alone. Eating doesn’t change how fast your liver clears alcohol once it’s in your blood, but it lowers the peak BAC you reach, which means less total clearance time.
Coffee and Cold Showers Don’t Help
Your body eliminates alcohol on a fixed schedule, and nothing you do externally changes that rate. Coffee won’t speed it up. Cold showers won’t speed it up. Exercise, fresh air, and energy drinks won’t either. According to the Hazelden Betty Ford Foundation, while a cold shower might make you feel more alert, it has no effect on your blood alcohol level. Caffeine can mask the feeling of intoxication, which actually makes it more dangerous because you may feel capable of driving when your BAC is still well above the legal limit.
The only thing that lowers your BAC is time.
How Long Alcohol Shows Up on Tests
Blood alcohol clears and test detection windows are two different things. Even after your BAC returns to zero, certain tests can still find evidence that you were drinking.
- Blood tests can detect alcohol for up to 12 hours after your last drink.
- Breathalyzers can detect alcohol on the breath for up to 24 hours, though 12 hours is more typical.
- Urine tests can detect alcohol metabolites for up to 5 days, depending on the type of test used. Standard urine tests have a shorter window, but tests that look for specific byproducts of alcohol metabolism can catch drinking several days later.
The blood and breath windows align fairly closely with actual BAC clearance. The urine window is much longer because your kidneys continue excreting breakdown products well after the alcohol itself is gone.
BAC Levels and Impairment
It’s worth knowing that impairment begins well before you reach the legal limit. At a BAC of just 0.02, most people experience altered mood, mild relaxation, and a slight decline in judgment. Reaction time and coordination begin to deteriorate noticeably around 0.05, which is the legal limit in Utah and many countries outside the United States. The 0.08 limit used in most U.S. states represents significant impairment in attention, speed control, and the ability to process information while driving.
The practical takeaway: if you’ve had several drinks in an evening, sleeping for a few hours may not be enough. A person who stops drinking at midnight with a BAC of 0.15 could still be above the legal driving limit at 7 or 8 the next morning. Planning an overnight gap between heavy drinking and driving is not always sufficient, especially after four or more drinks.