Alcohol leaves your body at a fairly fixed rate: about one standard drink per hour. So if you have three drinks, it takes roughly three hours for your body to fully process the alcohol. But “how long alcohol lasts” depends on what you mean. The buzz from a single drink fades within an hour or two, while traces of alcohol can show up on certain tests for days or even months.
How Your Body Processes Alcohol
Your liver does the heavy lifting. It uses two enzymes that work in sequence. The first converts alcohol into a toxic byproduct called acetaldehyde (a known carcinogen), and the second breaks acetaldehyde down into acetate, which your body easily converts to water and carbon dioxide. This process runs at a remarkably steady pace. Unlike most substances, alcohol doesn’t clear faster just because there’s more of it in your system. Your liver works through it like a conveyor belt, one drink at a time.
When you drink more than your liver can handle in an hour, the excess alcohol circulates in your blood, reaching your brain and other organs. That’s when you feel drunk. Each additional drink essentially adds another hour to your body’s processing queue.
How Long Until You’re Sober
The general rule of one drink per hour holds for most people, but the actual rate of alcohol clearance from your blood falls within a range of about 0.015 to 0.020 percent BAC per hour. For practical purposes, here’s what that looks like:
- 2 standard drinks: roughly 2 to 3 hours to reach zero BAC
- 4 standard drinks: roughly 4 to 6 hours
- 6 standard drinks: roughly 6 to 9 hours
A “standard drink” is 12 ounces of regular beer, 5 ounces of wine, or 1.5 ounces of liquor. Many cocktails and craft beers contain significantly more alcohol than one standard drink, which means you may be consuming more than you think. A strong IPA in a pint glass can easily count as two drinks.
Nothing speeds this process up. Coffee, cold showers, food, and water can make you feel more alert, but your liver still clears alcohol at the same fixed rate. Time is the only thing that actually lowers your BAC.
Why It Hits Some People Harder
Men and women process alcohol differently, and it’s not just about body size. Men produce the alcohol-clearing enzyme in both the stomach and the liver, and their liver version works faster. Women don’t produce this enzyme in the stomach at all, and the version in their liver is less efficient. This means women reach higher blood alcohol levels than men after the same number of drinks, even when weight is accounted for.
Body weight and composition matter too. A larger person has more water in their body to dilute alcohol, resulting in a lower BAC from the same number of drinks. People with more body fat and less water will reach higher concentrations faster.
Genetics also play a significant role. About 30% of people with East Asian ancestry carry a gene variant that reduces their ability to break down acetaldehyde, the toxic intermediate step. This leads to facial flushing, nausea, and a rapid heartbeat after drinking. It also slows overall alcohol processing, meaning the alcohol stays in the body longer and at higher concentrations.
How Long Alcohol Shows Up on Tests
Different tests look for different things, and their detection windows vary enormously.
A standard breathalyzer detects alcohol for roughly 12 to 24 hours after your last drink, depending on how much you consumed. Blood tests have a similar window. These methods measure the alcohol itself, so once your liver finishes processing it, you’ll test clean.
Urine testing is where it gets more complicated. A basic urine test catches alcohol for about 12 hours. But a more sensitive test looks for a metabolite called EtG, a byproduct your body produces when breaking down alcohol. EtG can be present in urine up to 48 hours after a few drinks, and sometimes 72 hours or longer after heavier drinking. This is the test commonly used in court-ordered monitoring and workplace programs.
Hair tests have the longest window by far. Alcohol metabolites get incorporated into growing hair and can be detected for 1 to 6 months, depending on hair length. It takes several weeks after drinking for the markers to appear in hair, so this test isn’t useful for detecting recent use. It’s designed to identify patterns of heavy drinking over time.
What About Liver Damage?
You might expect that people with liver disease would process alcohol more slowly, but research suggests otherwise. Studies comparing people with cirrhosis to those with healthy livers have found no compelling evidence that the clearance rate is much different. The normal range of alcohol elimination, about 0.015 to 0.020 BAC per hour, appears to hold even in people with significant liver scarring. That said, a damaged liver is far more vulnerable to additional harm from alcohol, even if it clears it at a normal pace.
The Morning After
One of the most practical concerns is whether you’re still over the legal limit the next morning. If you stop drinking at midnight after having six drinks, your body needs roughly six to nine hours to clear all the alcohol. That puts you at 6 to 9 a.m. before you’re at zero BAC. Many people are surprised to learn they could still blow over 0.08 on their morning commute after a night of heavy drinking.
Hangover symptoms can persist well beyond the point where alcohol has left your blood. Dehydration, inflammation, poor sleep quality, and residual acetaldehyde all contribute to feeling terrible even after your BAC reads zero. Feeling hungover doesn’t necessarily mean you still have alcohol in your system, but feeling fine doesn’t guarantee you’re clear either.