Four standard drinks take roughly 4 to 5 hours to fully leave your bloodstream, assuming average metabolism. But “your system” is broader than just blood. Depending on the type of test, alcohol or its byproducts can be detected in urine for up to 48 hours, in saliva for up to 24 hours, and in hair for months.
How Long Until Your BAC Hits Zero
Your liver breaks down alcohol at a fairly consistent pace: about 0.015 to 0.020 percent BAC per hour. You can’t speed this up with coffee, food, or water. Those things might help you feel more alert, but your liver works on its own clock.
For a rough estimate, a 160-pound man who drinks four standard drinks in about two hours will peak around 0.08 BAC, right at the legal limit in every U.S. state except Utah (which sets the limit at 0.05). At an average elimination rate of 0.015 per hour, it takes about 5 to 6 hours from the time you stop drinking to reach 0.00. A lighter person, or someone who drank faster, could peak higher and need longer.
A 140-pound woman drinking the same four drinks will typically reach a higher peak BAC, sometimes 0.10 or above. Women produce about 40% less of the liver enzyme that breaks down alcohol, and they generally have a higher body fat percentage, which concentrates alcohol in a smaller volume of body water. That means the same four drinks could take 6 to 7 hours to clear completely.
What Counts as “Four Drinks”
This math only works if you’re counting standard drinks correctly. In the U.S., one standard drink contains 0.6 ounces (14 grams) of pure alcohol. That’s:
- Beer: 12 ounces at 5% alcohol
- Wine: 5 ounces at 12% alcohol
- Liquor: 1.5 ounces (one shot) at 40% alcohol
- Malt liquor: 8 ounces at 7% alcohol
A pint of craft IPA at 7% is closer to 1.5 standard drinks. A generous restaurant pour of wine can easily be two. If your “four drinks” were actually six standard drinks worth of alcohol, add another hour or two to every estimate in this article.
Detection Windows by Test Type
If you’re asking this question because of an upcoming test, the answer depends entirely on what kind of test it is. Each one measures something different and has a different detection window.
Blood Test
A standard blood alcohol test detects alcohol for up to about 12 hours after your last drink. For four drinks, your blood will likely test clean within 5 to 8 hours, depending on your body and how quickly you drank.
Breath Test
Breathalyzers measure alcohol currently in your system, so the timeline closely mirrors your BAC. Once your BAC hits zero, a breathalyzer won’t pick anything up. For four drinks, expect 5 to 7 hours.
Saliva Test
Oral fluid tests can detect alcohol for up to 24 hours after drinking. Even after your BAC reads zero, trace amounts may still show in a saliva swab.
Urine Test (EtG)
This is where many people get caught off guard. A standard urine test detects alcohol itself for only 12 to 24 hours. But the more sensitive EtG (ethyl glucuronide) test picks up a metabolic byproduct your body creates when processing alcohol. After a few drinks, EtG can be present in urine for up to 48 hours, and sometimes 72 hours or longer with heavier drinking. Four drinks falls in that gray zone where detection at 48 hours is realistic.
Hair Test
Hair follicle tests look for EtG markers embedded in the hair shaft. A single session of four drinks may or may not trigger a positive result, but alcohol use generally shows up in hair for 1 to 6 months. It takes several weeks after drinking for markers to appear, so this test isn’t used to catch recent, one-time drinking. It’s designed to identify patterns.
Factors That Slow Elimination
The 0.015 per hour figure is an average, and real-world metabolism varies quite a bit. Several things push you toward the slower end:
- Body size and composition: Smaller people and those with higher body fat reach higher BAC levels from the same number of drinks, which means more time to clear.
- Biological sex: Women metabolize alcohol more slowly due to lower levels of the key liver enzyme and differences in body water volume.
- Liver health: Any existing liver damage or reduced liver function slows the process. Chronic heavy drinking gradually impairs the liver’s ability to keep up.
- Medications: Acetaminophen (Tylenol) is processed by the same liver pathway as alcohol. Taking both creates a bottleneck where alcohol clears more slowly and the drug is metabolized incorrectly, which can also damage liver cells.
- Food intake: Drinking on an empty stomach leads to faster absorption and a higher peak BAC. Food doesn’t speed up elimination, but it lowers the peak you have to come down from.
A Realistic Timeline for Four Drinks
Here’s a practical scenario: you have four beers over two hours at dinner, finishing your last one at 10 p.m. Your BAC peaks somewhere around 0.07 to 0.09 shortly after that last drink. At a typical elimination rate, you’d hit 0.00 between 3 and 5 a.m. By morning, a breathalyzer or blood test would likely come back clean.
A saliva test could still detect alcohol the next morning. An EtG urine test could flag positive into the following evening, potentially up to 48 hours after your last drink. And if you’re subject to hair testing, that night’s drinking could theoretically appear in a sample collected weeks later.
The legal limit for driving is 0.08 BAC in 49 states and 0.05 in Utah. Four drinks can put you right at or above 0.08, which means you may still be over the legal limit an hour or two after your last drink even if you feel fine. Feeling sober and being under the limit are not the same thing.