Alcohol leaves your system at a roughly fixed rate: about one standard drink per hour. Your liver does nearly all the work, and it can’t be rushed. So if you have four drinks, expect it to take around four to five hours for your blood alcohol level to return to zero. But “leaving your system” means different things depending on whether you’re talking about feeling sober, passing a breathalyzer, or clearing a urine test, and the timelines for each are quite different.
How Your Liver Processes Alcohol
When you drink, your liver prioritizes alcohol above everything else it normally does, including regulating blood sugar. It breaks ethanol down in two stages. First, it converts alcohol into a compound called acetaldehyde, which is actually more toxic than the alcohol itself. Then a second enzyme converts acetaldehyde into acetate, a harmless substance your body can use for energy or excrete.
This process runs at a near-constant speed. The liver eliminates roughly one standard drink per hour, and if there’s more alcohol in your blood than the liver can handle, the excess just keeps circulating until the liver catches up. There’s no way to accelerate the process. In the United States, one standard drink contains 0.6 ounces (14 grams) of pure alcohol. That’s 12 ounces of regular beer, 5 ounces of wine, or 1.5 ounces of distilled spirits.
A Rough Timeline by Number of Drinks
Since metabolism is roughly one drink per hour, you can estimate clearance with simple math. Two standard drinks take about two to three hours. Four drinks take roughly four to five hours. A heavy night of eight or more drinks could mean alcohol is still in your bloodstream well into the next morning or even the next afternoon. Keep in mind these are estimates for a person of average size. If your drinks were stronger than standard (a large pour of wine, a double cocktail), each one counts as more than one unit in this calculation.
Why the Timeline Varies From Person to Person
The one-drink-per-hour rule is an average, and several factors shift it in either direction.
Body size and composition. A larger person with more muscle and water in their body will dilute alcohol more effectively, resulting in a lower peak blood alcohol level from the same number of drinks. Body fat doesn’t absorb alcohol well, so two people who weigh the same can have different blood alcohol levels if one carries more fat and less muscle.
Biological sex. Women generally absorb more alcohol and take longer to process it than men, even at the same body weight. This is partly because women tend to have a higher proportion of body fat and lower total body water. The distribution factor used in forensic calculations is about 0.7 for men and 0.6 for women of normal weight, meaning alcohol concentrates more in a woman’s body from an identical dose.
Food in your stomach. Eating before or while drinking slows the rate at which alcohol reaches your small intestine, where most absorption happens. In one study, alcohol disappeared from the stomach far more slowly when consumed with food, and a greater share was broken down before ever reaching the bloodstream. Drinking on an empty stomach lets alcohol hit your blood faster and produces a higher peak level, which then takes longer to clear.
Genetics. Your DNA plays a surprisingly large role. Some people carry gene variants that speed up the first step of alcohol breakdown by 80 to 100 times, flooding the body with acetaldehyde. Others carry variants that cripple the second step, leaving acetaldehyde lingering. People with the slow-clearance variant, common in East Asian populations, can experience intense facial flushing, rapid heartbeat, and nausea from even small amounts of alcohol. If you’ve ever turned red after a single drink, this is likely why. It’s not a quirky reaction; it means acetaldehyde is accumulating because your body can’t clear it efficiently. That acetaldehyde is classified as a carcinogen and can directly damage DNA.
Detection Windows for Different Tests
Your body may feel sober hours before every trace of alcohol and its byproducts disappears. How long alcohol remains detectable depends on the type of test.
- Breath (breathalyzer): Detects alcohol as long as it’s actively in your bloodstream, typically aligning with the one-drink-per-hour clearance rate. After your last drink, a breathalyzer can pick up alcohol for roughly 12 to 24 hours depending on how much you consumed.
- Saliva: Alcohol can be detected in saliva for up to 24 hours after drinking.
- Urine (standard test): A basic urine test picks up alcohol for roughly 12 to 24 hours. However, the more sensitive EtG urine test, which looks for a specific metabolic byproduct, can detect drinking for up to 48 hours after a few drinks, and sometimes 72 hours or longer after heavier consumption.
- Hair: Hair follicle tests have the longest window, potentially detecting alcohol use for up to 90 days, though they reflect patterns of use rather than a single episode.
If you’re facing a workplace or legal test, the EtG urine test is the one most people underestimate. A Friday night of heavy drinking can still produce a positive result on Monday morning.
What Doesn’t Speed Things Up
Coffee, cold showers, exercise, energy drinks, and greasy food do nothing to help your liver work faster. Coffee might make you feel more alert, but it doesn’t lower your blood alcohol level. A cold shower produces a cold, wet person who is still impaired. Time is the only thing that actually clears alcohol from your body. Your liver sets the pace, and no outside intervention changes it.
Drinking water and eating food can help you feel better and may slow further absorption if you’re still drinking, but they won’t accelerate the elimination of alcohol that’s already in your bloodstream.
Putting It Into Practice
If you’re trying to figure out when you’ll be completely clear, count your standard drinks honestly (remembering that a strong cocktail or large glass of wine may count as two), then allow at least one hour per drink from the time you stopped. Add an extra hour or two as a buffer, since most people undercount their intake, and individual variation means the one-drink-per-hour figure isn’t guaranteed for everyone.
For a concrete example: if you finish your last drink at midnight and you’ve had six standard drinks over the evening, your blood alcohol level likely won’t reach zero until roughly 6 to 8 a.m. You may feel fine well before that, but your body is still processing alcohol, and a breathalyzer or blood test would confirm it.