Alcohol is detectable in your body anywhere from 12 hours to 90 days after your last drink, depending on the type of test. Your blood and breath clear it fastest, while hair holds evidence of past drinking for months. The specific window depends on how much you drank, your body composition, and which test is being used.
Detection Windows by Test Type
Different tests look for different things. Some measure alcohol itself, while others detect byproducts your body creates while breaking it down. Here’s how long each method can pick up evidence of drinking:
- Blood: Up to 12 hours after your last drink.
- Breath: Up to 24 hours. A breathalyzer measures alcohol vapor crossing from your bloodstream into your lungs, so the window closely tracks your blood alcohol level.
- Standard urine test: Roughly 12 to 24 hours for a basic screening that looks for alcohol itself.
- EtG urine test: Up to 48 hours after a few drinks, and sometimes 72 hours or longer after heavier drinking. This test detects a metabolic byproduct called ethyl glucuronide rather than alcohol directly, which is why the window is so much wider.
- Hair follicle: Up to 90 days. Alcohol byproducts get trapped in the hair shaft as it grows, creating a timeline of past use.
If you’re facing a workplace screening, most employers use urine panels. Court-ordered or probation testing often uses the more sensitive EtG version. Roadside stops rely on breath. Knowing which test you’re dealing with matters more than a single blanket number.
How Your Body Breaks Down Alcohol
Nearly all the alcohol you drink is processed by your liver. The process happens in two steps. First, an enzyme converts ethanol into acetaldehyde, a toxic intermediate that causes many of the unpleasant effects of heavy drinking. A second enzyme then converts acetaldehyde into acetic acid, essentially vinegar, which your body can safely use for energy.
What makes alcohol unique compared to most drugs is that your liver can only process it at a fixed rate. The enzymes responsible for clearing alcohol become fully saturated after just one drink. Once that happens, it doesn’t matter how high your blood alcohol climbs. Your liver still works at the same steady pace. The practical result: you can’t speed up sobering by drinking water, eating food, or exercising. Those things may help you feel better, but they don’t change how fast alcohol leaves your blood.
The Average Clearance Rate
A healthy adult clears alcohol from the blood at roughly 0.015 to 0.020 percent per hour. In clinical terms, that’s about 20 mg/dL per hour, and the liver processes approximately 7 to 10 grams of pure alcohol in that time. For context, one standard drink in the United States contains 14 grams of pure alcohol, whether that’s a 12-ounce beer, a 5-ounce glass of wine, or a 1.5-ounce shot of liquor.
So a single standard drink takes roughly 1.5 to 2 hours to fully clear your bloodstream. Three drinks might take 4.5 to 6 hours. Five drinks could keep alcohol in your blood for 7.5 to 10 hours. These are averages. Your actual rate depends on several biological factors.
Why Some People Process Alcohol Faster
Sex is one of the biggest variables. Women typically reach higher blood alcohol levels than men from the same amount of alcohol, and they stay elevated longer. Part of the reason is body composition: women generally carry more body fat and less water, so alcohol is more concentrated in the bloodstream. But there’s also an enzymatic difference. Men produce a stomach enzyme that breaks down about 30 percent of the alcohol before it ever reaches the bloodstream. In women, the gene for this enzyme is essentially switched off, meaning more alcohol passes directly into the blood.
Genetics play a role beyond sex as well. About half of people of East Asian descent inherit a gene variant that produces a nonfunctional version of the second liver enzyme in the breakdown chain. Without that enzyme working properly, the toxic intermediate builds up to levels 20 times higher than normal. This causes the facial flushing, nausea, and rapid heartbeat sometimes called “Asian flush.” It also means acetaldehyde lingers in the body much longer.
Body weight matters because alcohol distributes through water in your body. A larger person has more total body water to dilute the alcohol, so a 200-pound person will generally have a lower peak blood alcohol level than a 130-pound person after the same number of drinks. Age slows things down as well, since liver function and enzyme production gradually decline. A 60-year-old will typically process alcohol more slowly than a 25-year-old.
Chronic heavy drinkers can actually develop a faster clearance rate over time. Their livers recruit a secondary processing system that activates in response to regular high-volume exposure. This doesn’t mean heavy drinkers are safer. It means their bodies are working harder and sustaining more liver damage in the process.
How Food Changes the Timeline
Eating before or while drinking doesn’t change how fast your liver processes alcohol, but it significantly slows how quickly alcohol enters your bloodstream in the first place. About 20 percent of alcohol is absorbed through the stomach wall, and the remaining 80 percent passes into the small intestine where absorption is much faster. When food is present, especially protein and fat, a valve between the stomach and small intestine closes. This keeps alcohol in the stomach longer, slowing the rate at which it reaches your blood.
The practical effect: drinking on a full stomach produces a lower, flatter peak in blood alcohol compared to drinking the same amount on an empty stomach. You still absorb all the alcohol eventually, but the peak is blunted enough that your liver has a better chance of keeping up. On an empty stomach, alcohol hits the small intestine almost immediately and blood alcohol spikes faster than your liver can respond.
Blood Alcohol Level and Timing
Your blood alcohol concentration (BAC) peaks about 30 to 60 minutes after your last drink if you’re on an empty stomach, or up to 90 minutes with food. From that peak, the steady decline begins at roughly 0.015 percent per hour. If your BAC peaks at 0.08 (the legal driving limit in most U.S. states), it would take about 5.5 hours to reach zero.
A common miscalculation is assuming you’re fine to drive after sleeping. If you stop drinking at midnight with a BAC of 0.12, your body won’t finish processing that alcohol until roughly 8 a.m. A breathalyzer could still register a positive reading when you leave for work. People arrested for DUI the morning after a night of heavy drinking are not unusual.
Keep in mind that impairment starts well below the legal limit. Reaction time, judgment, and coordination begin to deteriorate at BAC levels as low as 0.02, which for many people is less than one full drink.