Your body eliminates roughly one standard drink per hour, but alcohol can remain detectable in your system for much longer depending on the type of test. A standard breathalyzer or blood test picks up alcohol for about 12 to 24 hours after your last drink, while a urine test using specialized biomarkers can flag drinking up to five days later. Hair tests extend that window to several months.
How Your Body Processes Alcohol
The liver does the heavy lifting. Two enzymes work in sequence: the first converts alcohol into a toxic intermediate compound called acetaldehyde (a known carcinogen), and the second breaks acetaldehyde down into acetate, which your body then converts to water and carbon dioxide. A 70-kilogram person (about 154 pounds) can process roughly 170 to 240 grams of alcohol per day, which works out to about 7 grams per hour, or approximately one standard drink.
A standard drink in the United States contains 14 grams of pure alcohol. That’s 12 ounces of regular beer, 5 ounces of wine, or 1.5 ounces of distilled spirits. If you have three drinks in an hour, your body can only clear one of them in that time. The remaining alcohol stays in your bloodstream until your liver catches up, which is why drinking faster than one drink per hour causes your blood alcohol level to climb.
Detection Windows by Test Type
The answer to “how long” depends entirely on what’s being tested and how sensitive the test is.
- Breath: Standard breathalyzers detect alcohol for roughly 12 to 24 hours after your last drink. Testing should be done at least 20 minutes after the last sip to avoid false readings from residual alcohol in the mouth.
- Blood: Alcohol is detectable in a blood draw for a similar window as breath testing, typically up to 12 hours, though this varies with how much you drank.
- Saliva: Oral fluid tests can pick up alcohol for about 12 to 24 hours. Samples should be collected at least 10 minutes after eating or drinking anything to get an accurate result.
- Urine (standard): A conventional urine test detects ethanol itself for roughly 12 to 48 hours.
- Urine (EtG): This more sensitive test looks for ethyl glucuronide, a byproduct your body creates when processing alcohol. At the most sensitive cutoff (100 ng/mL), it can detect heavy drinking for up to five days and any drinking within the previous two days. At a higher cutoff of 500 ng/mL, the test is likely to catch only heavy drinking from the previous day.
- Hair: Hair follicle tests detect alcohol biomarkers for 1 to 6 months after consumption. These tests measure long-term patterns rather than single drinking episodes.
What Affects How Fast You Clear Alcohol
Your genetics play a bigger role than most people realize. A key enzyme involved in breaking down acetaldehyde comes in different genetic variants. People who carry an efficient version of this enzyme clear alcohol at nearly twice the rate of those with a less active variant. This genetic difference is particularly common among people of East Asian descent and explains why some individuals experience intense facial flushing and nausea after even small amounts of alcohol.
Interestingly, biological sex has less impact on the elimination rate than commonly believed. A 2024 study found no significant difference in how quickly men and women cleared ethanol from their blood. However, women typically reach higher blood alcohol levels than men after the same number of drinks because they tend to have lower body water content and smaller body size, meaning the same amount of alcohol gets distributed into less fluid.
Food is another factor people often ask about, but its effect is more nuanced than expected. Eating before or while drinking slows the absorption of alcohol into your bloodstream, which generally means a lower peak blood alcohol concentration. However, research shows the total time to reach zero blood alcohol is essentially the same whether your stomach is full or empty (about 5 hours for a moderate dose in one study). Food smooths the curve but doesn’t meaningfully shorten the overall clearance time.
How Many Drinks and How Long to Zero
Since your liver clears about one drink per hour, you can make a rough estimate. Two drinks will take approximately two to three hours to fully metabolize. Four drinks might take four to six hours. A night of heavy drinking (eight or more drinks) could mean alcohol is still in your blood well into the next afternoon. These are ballpark figures because metabolism isn’t perfectly linear. At higher concentrations, your liver’s enzymes become saturated, and the rate of elimination can shift.
Keep in mind that feeling sober is not the same as being at zero. Many people feel “fine” while still carrying a measurable blood alcohol concentration. The legal limit for driving is 0.08% in every U.S. state except Utah, which uses 0.05%. A person who stops drinking at midnight after several drinks could still be above the legal limit the next morning.
Why EtG Tests Catch Drinking Days Later
EtG (ethyl glucuronide) deserves special attention because it’s increasingly used in court-ordered testing, workplace programs, and medical monitoring. Unlike a breathalyzer that measures alcohol itself, an EtG test detects a metabolic byproduct that your body produces in small quantities and excretes through urine over a longer period.
At the standard 100 ng/mL cutoff, this test identified 85% of light drinking episodes from the previous day and still caught 66% of them five days later. For heavy drinking, detection rates stayed between 79% and 84% across the full five-day window. At the stricter 500 ng/mL cutoff, detection dropped significantly for light drinking (68% on day one, under 58% after that) but remained reasonably high for heavy drinking on the day after (78%).
This means the sensitivity of the test matters a great deal. If you’re subject to EtG testing with a low cutoff, even a couple of drinks could show up two or three days later. Some products like certain mouthwashes and hand sanitizers contain enough alcohol to trigger very sensitive EtG tests, which is why the cutoff threshold is set based on the testing program’s goals.
The Bottom Line on Timing
For practical purposes: if you need to pass a standard breath or blood test, allow at least one hour per drink plus a buffer. If you’re facing an EtG urine test, even moderate drinking can be detected two to three days out, and heavy drinking up to five days. Hair tests look back months, not hours. No amount of water, coffee, or exercise speeds up your liver’s fixed processing rate.