For most people, the body eliminates alcohol at a rate of about 0.015% blood alcohol concentration (BAC) per hour. That means a single standard drink typically clears your bloodstream in roughly one to two hours, while a night of heavier drinking could take 12 hours or more. But “leaving your body” depends on what you mean: alcohol itself disappears from blood and breath relatively quickly, while certain byproducts remain detectable in urine for days and in hair for months.
How Your Body Breaks Down Alcohol
Your liver does the heavy lifting. It uses two enzymes in sequence to dismantle alcohol molecules. The first converts alcohol into a toxic compound called acetaldehyde, a known carcinogen. Fortunately, acetaldehyde is short-lived. A second enzyme quickly converts it into acetate, which your body then breaks down into water and carbon dioxide for easy elimination.
This process is remarkably steady. Unlike most substances, alcohol is metabolized at a near-constant rate regardless of how much is in your system. Your liver can only work so fast, which is why drinking faster than your body can process leads to rising BAC. A backup enzyme system kicks in after heavy drinking to help, but under normal circumstances your liver handles virtually all of it on its own.
The Standard Elimination Rate
Research on elimination rates places the typical range between 0.010% and 0.020% BAC per hour. If you drank on an empty stomach, the rate tends to fall in the lower end of that range (roughly 0.010 to 0.015%). If you ate beforehand, elimination runs closer to 0.015 to 0.020% per hour. For moderate drinkers, 0.015% per hour is a reliable average.
To put that into practical terms: one standard drink in the United States contains 0.6 ounces (14 grams) of pure alcohol. That’s 12 ounces of regular beer at 5%, 5 ounces of wine at 12%, or a 1.5-ounce shot of 80-proof liquor. One of those drinks raises BAC by roughly 0.02 to 0.03% in most adults, meaning it takes about one to two hours to fully metabolize. Four drinks bringing you to around 0.08% would take approximately five to six hours to clear completely.
Why It Takes Longer for Some People
Several biological factors change how quickly you process alcohol. The biggest one is sex. Men eliminate alcohol from their blood roughly 27% faster than women on average, largely because of differences in liver size and lean body mass. A larger liver has more capacity to break down alcohol at any given moment.
Body composition matters too. Muscle tissue absorbs alcohol, but fat tissue does not. Two people who weigh the same but carry different amounts of body fat will reach different BAC levels from the same number of drinks. The person with more body fat will typically hit a higher peak BAC and take longer to return to zero.
Age, interestingly, appears to have less impact than most people assume. A study that specifically tested whether older adults metabolize alcohol more slowly found no significant difference in elimination rates between age groups once sex and body size were accounted for. That said, older adults often feel the effects more intensely because of changes in body water content and overall tolerance.
Eating before or during drinking affects peak BAC more than total elimination time. A meal high in carbohydrates can meaningfully reduce your peak blood alcohol level, which means your body has less total alcohol to process. But food doesn’t speed up the liver’s work rate. It simply slows absorption, spreading the load over a longer window and preventing a sharp spike.
How Long Alcohol Shows Up on Different Tests
The answer to “how long does alcohol stay in your system” changes dramatically depending on the type of test.
Blood and Breath
Standard blood tests and breathalyzers detect alcohol itself, not its byproducts. Alcohol is generally detectable in blood for up to 12 hours after your last drink, though the exact window depends on how much you consumed. Breath tests track closely with blood levels and have a similar detection window. One thing worth knowing: residual alcohol in your mouth can inflate a breathalyzer reading for 10 to 19 minutes after your last sip. That’s why law enforcement officers are trained to observe a waiting period before administering the test.
Urine
Standard urine tests detect alcohol for roughly 12 to 24 hours. But many testing programs now use a more sensitive marker called EtG (ethyl glucuronide), a byproduct your liver produces when processing alcohol. EtG lingers far longer than alcohol itself. After a few drinks, it can show up in urine for 48 hours. After heavier drinking, detection extends to 72 hours or more.
The sensitivity of EtG testing depends on the cutoff level the lab uses. At the most sensitive cutoff (100 ng/mL), the test can identify heavy drinking up to five days later and catches about 85% of even light drinking within the first day. At a higher cutoff of 500 ng/mL, detection is largely limited to heavy drinking within the previous 24 hours. If you’re being tested for a specific program, the cutoff level matters a great deal for how far back the test can “see.”
Hair
Hair follicle tests have the longest detection window. Alcohol markers typically appear in hair for three to six months, though they can persist even longer in hair that hasn’t been cut. These tests are less common and are generally used for ongoing monitoring rather than detecting a single episode of drinking.
A Rough Timeline for Common Scenarios
These estimates assume an average-sized adult metabolizing at 0.015% BAC per hour. Your individual timeline will vary based on the factors above.
- 1 to 2 standard drinks: Alcohol clears from blood in roughly 2 to 3 hours.
- 3 to 4 standard drinks: Expect 4 to 6 hours before BAC reaches zero.
- 5 to 6 standard drinks: Full clearance takes approximately 7 to 10 hours.
- A heavy night (8+ drinks): You could still have measurable BAC 12 or more hours later, well into the next morning or afternoon.
These timelines cover only blood and breath. Urine EtG and hair tests extend the window considerably, as described above.
Why You Can’t Speed It Up
Coffee, cold showers, exercise, and “sweating it out” do not accelerate alcohol metabolism. Your liver processes alcohol at a fixed rate, and nothing you do externally changes that. Coffee might make you feel more alert, but your BAC stays the same. Drinking water helps prevent dehydration but won’t clear alcohol from your blood any faster.
The only thing that reliably lowers your BAC is time. If you need to be completely sober for driving, work, or a test, the safest approach is to count your drinks, estimate your peak BAC, and give yourself enough hours for your liver to do its job.