Your body clears alcohol at a fairly steady rate of about 0.015 to 0.02 BAC per hour, which works out to roughly one standard drink every 60 to 90 minutes. So if you stop drinking at midnight with a BAC of 0.08 (the legal limit in most U.S. states), you’d be back to 0.00 somewhere between 4:00 and 5:30 a.m. But “out of your system” means different things depending on whether you’re talking about feeling sober, passing a breathalyzer, or clearing a urine test.
How Fast Your Liver Processes Alcohol
Alcohol is broken down primarily in your liver by an enzyme that converts it into a toxic intermediate compound, which is then quickly broken down further into harmless byproducts your body can eliminate. The average clearance rate measured in clinical studies is about 20 to 23 mg/dL per hour. In practical terms, that means a person with a moderate blood alcohol level will drop roughly 0.015 to 0.02 percentage points of BAC every hour.
This rate is remarkably consistent. Unlike many substances, alcohol is processed at a near-fixed speed regardless of how much you’ve had. Your liver can only work so fast. Drinking coffee, taking a cold shower, or exercising won’t change that speed. The only thing that truly clears alcohol from your blood is time.
Rough Timelines by Number of Drinks
One standard drink in the U.S. contains about 14 grams of pure alcohol. That’s a 12-ounce beer, a 5-ounce glass of wine, or a 1.5-ounce shot of liquor. Using the average metabolism rate, here’s approximately how long it takes for the alcohol itself to leave your bloodstream after your last sip:
- 1 to 2 drinks: 1 to 3 hours
- 3 to 4 drinks: 3 to 6 hours
- 5 to 6 drinks: 5 to 9 hours
- A heavy night (8 to 10 drinks): 10 to 15 hours or more
These are estimates for the average adult. If you had 10 drinks and your last one was at 1:00 a.m., you could still have measurable alcohol in your blood well into the following afternoon.
Detection Windows for Different Tests
Alcohol itself clears your blood and breath relatively quickly, but your body produces byproducts that linger much longer. The type of test determines how far back it can look.
Breath and blood tests detect alcohol itself and are only reliable for roughly 12 to 24 hours after your last drink. A standard breathalyzer will read zero once your liver has finished processing the alcohol in your blood.
Standard urine tests can pick up alcohol for about 12 to 24 hours. But more advanced urine tests look for a metabolite called EtG, a byproduct your body creates when processing alcohol. EtG typically shows up for 24 to 72 hours after drinking, and in cases of heavy consumption, it can be detected for up to 80 hours. This is the test commonly used for court-ordered monitoring, workplace programs, and treatment compliance.
Hair follicle tests have the longest window by far. Alcohol markers can appear in a strand of hair for 1 to 6 months after use. These tests aren’t measuring a single night of drinking; they’re looking at patterns over time.
What Slows Down or Speeds Up Clearance
While the liver’s processing speed is relatively fixed, several factors affect how high your BAC climbs in the first place and how long you stay above zero.
Body composition and sex. Women generally reach higher blood alcohol levels than men after drinking the same amount, primarily because women tend to have a lower proportion of body water, which means alcohol is more concentrated in the bloodstream. Men also tend to eliminate alcohol faster in absolute terms (grams per hour), largely because of differences in lean body mass and liver size. A smaller liver simply has less capacity to process alcohol at any given moment.
Food in your stomach. Eating before or while drinking slows the rate at which alcohol enters your bloodstream. Solid meals are especially effective because they delay the emptying of your stomach, giving your liver more time to keep up with incoming alcohol. Some research also suggests that food increases the rate at which your body eliminates alcohol, though the primary benefit is a lower, slower peak BAC rather than dramatically faster clearance.
Drinking history. People who drink regularly tend to metabolize alcohol slightly faster. Studies in emergency department patients, who often had histories of heavy use, found clearance rates averaging 23 mg/dL per hour, somewhat higher than the 15 to 20 mg/dL per hour typically seen in lighter drinkers. This doesn’t mean tolerance is protective; it means the liver has adapted to a higher workload, which comes with its own health costs.
Age. Older adults generally process alcohol more slowly, partly due to decreased liver function and changes in body composition that come with aging.
What Water and Coffee Actually Do
Drinking water between alcoholic drinks is genuinely helpful, but not because it speeds up metabolism. Water slows your overall pace of drinking, giving your liver more time to process each round. It also helps prevent dehydration, which is responsible for much of the headache and fatigue you feel the next day. But it doesn’t make your liver work faster. The same goes for coffee: caffeine can make you feel more alert, but your BAC remains exactly where it would be without it.
Withdrawal Is Different From Clearance
For most people who had a few drinks on a Friday night, the question is simply when they’ll be sober. But for heavy or long-term drinkers, the body’s adjustment to the absence of alcohol is a separate and more serious process.
Mild withdrawal symptoms like headache, anxiety, and insomnia can start within 6 to 12 hours of the last drink. Symptoms typically peak between 24 and 72 hours. In severe cases, the risk of seizures is highest 24 to 48 hours after the last drink, and a dangerous condition called delirium tremens can appear between 48 and 72 hours. This is not the same as a hangover. If you drink heavily on a daily basis and are planning to stop, doing so under medical supervision is significantly safer.
Practical Takeaways for Timing
If you need to drive, the simplest rule of thumb is one hour per standard drink after you stop, plus one extra hour as a buffer. Had four beers ending at midnight? Plan on being safe to drive around 5:00 a.m. at the earliest. Keep in mind that cocktails and craft beers often contain more alcohol than a single standard drink, so count carefully.
If you’re facing a urine test, alcohol itself will clear within a day, but the EtG metabolite can persist for up to 80 hours after heavy drinking. For a hair test, there’s no short-term strategy: it reflects months of use. For a breathalyzer or blood draw, you’re looking at roughly 12 to 24 hours depending on how much you consumed. The math isn’t complicated, but most people underestimate how many standard drinks they actually had, which is where the timeline falls apart.