For most people, the body clears alcohol from the bloodstream at a rate of about 0.015 to 0.020 BAC per hour. That means if you’re at the legal driving limit of 0.08 BAC, it takes roughly 4 to 5 hours to reach zero. But “out of your system” depends on what you mean: alcohol itself is gone from your blood within hours, while certain byproducts can be detected in urine for up to 5 days and in hair for 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 compound called acetaldehyde (a known carcinogen), and the second quickly breaks acetaldehyde down into acetate, which your body then converts to water and carbon dioxide for easy elimination.
The key limitation is that the first enzyme gets saturated at relatively low alcohol concentrations. Once that happens, your liver can only process alcohol at a fixed pace, no matter how much is in your blood. This is why drinking more doesn’t speed up the process. It just means there’s more alcohol waiting in line. Your liver processes roughly one standard drink per hour, where a standard drink contains about 14 grams of pure alcohol. That’s one 12-ounce beer, one 5-ounce glass of wine, or one 1.5-ounce shot of liquor.
Estimated Clearance Times by Number of Drinks
Using the average clearance rate of 0.015 to 0.020 BAC per hour, here’s a rough timeline for how long it takes to reach zero BAC. These numbers assume average body composition and normal liver function:
- 1 to 2 drinks: approximately 1 to 3 hours
- 3 to 4 drinks: approximately 4 to 6 hours
- 5 to 6 drinks: approximately 6 to 9 hours
- 8 to 10 drinks: approximately 10 to 14 hours
These are estimates. Two people who drink the same amount can have very different timelines depending on their body size, sex, and liver health.
Detection Windows by Test Type
If you’re wondering about a specific type of test, the detection window varies dramatically depending on whether the test looks for alcohol itself or for metabolic byproducts your body produces while breaking it down.
- Breath test (breathalyzer): detects alcohol for up to 24 hours after drinking, though 12 hours is more typical for moderate amounts.
- Blood test: detects alcohol for up to 12 hours.
- Saliva test: detects alcohol for up to 24 hours.
- Standard urine test: detects alcohol for 12 to 24 hours in most cases.
- EtG urine test: detects a metabolic byproduct of alcohol for up to 5 days after heavy drinking. At lower sensitivity cutoffs, it typically catches heavy drinking within the previous day only.
- Hair follicle test: detects alcohol use for 1 to 6 months, though most results reflect the previous 3 months since hair is usually trimmed before growing longer.
The EtG test deserves special attention because it catches people off guard. It doesn’t measure alcohol directly. Instead, it detects ethyl glucuronide, a compound your liver produces as it processes alcohol. At its most sensitive cutoff (100 ng/mL), the EtG test detected 84% of heavy drinking episodes one day later and still caught 79% of them five days later. At a higher cutoff of 500 ng/mL, it typically only flags heavy drinking from the previous day.
What Affects How Fast You Clear Alcohol
Body Size and Composition
Alcohol dissolves in water, not fat. So two people of the same weight can reach different BAC levels if one carries more body fat. The person with a higher fat percentage has less body water to dilute the alcohol, resulting in a higher peak BAC and a longer time to clear it completely.
Sex
Women typically reach higher peak blood alcohol levels than men when given the same dose of alcohol per kilogram of body weight. This is primarily because women tend to have a higher percentage of body fat and a smaller volume of body water to distribute the alcohol into. However, when researchers correct for lean body mass, women actually eliminate alcohol slightly faster than men. The net effect is that women often hit a higher peak but the per-hour clearance rate is roughly similar between sexes.
Age
There’s a small decline in alcohol elimination as you get older, likely because liver mass and total body water both decrease with age. The difference isn’t dramatic, but it means a 60-year-old may take somewhat longer to clear the same number of drinks compared to a 30-year-old.
Liver Health
Since your liver handles nearly all alcohol metabolism, any significant liver damage slows the process. Advanced liver disease noticeably decreases the rate your body can break down alcohol, meaning it stays in your system longer at higher concentrations.
Food
Eating before drinking is commonly thought to help you “sober up faster,” but the reality is more nuanced. In a controlled study where participants drank the same amount of alcohol on a full stomach versus after a six-hour fast, the elimination rate was actually slightly lower after eating (0.017 per hour vs. 0.020 per hour on an empty stomach). The total time to reach zero was virtually identical: about 5 hours either way. Food does lower your peak BAC by slowing absorption, which means you feel less intoxicated, but it doesn’t meaningfully speed up how quickly alcohol leaves your body.
What Doesn’t Speed Up the Process
Coffee, cold showers, exercise, and drinking water are all commonly suggested as ways to sober up faster. None of them increase the rate your liver processes alcohol. Coffee may make you feel more alert, but your BAC remains unchanged. Drinking water helps with hydration and can reduce hangover severity, but it doesn’t pull alcohol out of your bloodstream any faster. Your liver sets the pace, and it can’t be rushed.
The only thing that reliably clears alcohol from your system is time. If you had your last drink at midnight and consumed enough to reach a BAC of 0.08, you’re looking at roughly 4 to 5 hours before your blood alcohol hits zero. If you drank heavily and reached 0.15 or higher, that timeline extends to 10 hours or more. Planning accordingly, especially before driving or taking a test, is the only reliable strategy.