Most people eliminate alcohol at a rate of about 0.015 to 0.020 grams per deciliter of blood per hour, which works out to roughly one standard drink every 60 to 90 minutes. But “how long alcohol lasts” depends on what you mean: how long you feel its effects, how long it takes your blood alcohol to hit zero, or how long a test can pick it up. Those are three very different timelines.
How Your Body Breaks Down Alcohol
Your liver does the heavy lifting. It processes alcohol in two steps. First, an enzyme called alcohol dehydrogenase converts alcohol into acetaldehyde, a toxic compound responsible for many of the unpleasant effects of drinking. Then a second enzyme converts acetaldehyde into acetate, which your body can safely use for energy or excrete.
The catch is that your liver can only handle so much at once. The maximum elimination rate for a 70-kilogram (154-pound) person is about 8.5 grams per hour. One standard drink in the United States contains 14 grams of pure alcohol, so even at peak capacity your liver needs roughly 90 minutes to fully process a single drink. When you drink faster than your liver can keep up, alcohol accumulates in your blood and you get progressively more intoxicated.
This is why you can’t meaningfully speed up sobriety. Coffee, cold showers, and exercise don’t increase your liver’s processing speed. The only thing that clears alcohol from your system is time.
A Realistic Timeline for Common Scenarios
If you have two drinks over dinner, your body needs roughly two to three hours to fully metabolize the alcohol. Four drinks over a couple of hours could take five to six hours. A heavy night of eight or more drinks might leave measurable alcohol in your blood well into the next morning, sometimes 10 to 12 hours after you stopped drinking.
These numbers assume average metabolism. Some people clear alcohol slightly faster, others slower. But the ballpark holds: plan on about one hour per drink as a minimum, and longer if you drank quickly or on an empty stomach.
What Slows Down (or Speeds Up) the Process
Food is the single biggest variable. Eating before or while drinking keeps alcohol in your stomach longer, where absorption is much slower than in the small intestine. A heavy meal can dramatically lower your peak blood alcohol level compared to drinking on an empty stomach, even if you consume the same amount. Animal studies show that even four hours after drinking, 10 to 20 percent of the original dose can still be sitting in the stomach when food is present. This doesn’t mean food helps you sober up faster. It means alcohol enters your bloodstream more gradually, producing a lower peak but a longer, flatter curve.
Biological sex matters too. Women tend to have higher levels of the primary alcohol-processing enzyme in their liver, which sounds like an advantage but actually creates a faster buildup of acetaldehyde, the toxic intermediate. Women also generally have lower body water content, meaning the same number of drinks produces a higher blood alcohol concentration. Body size, liver health, genetics, and how frequently you drink all play roles as well.
Detection Windows by Test Type
Different tests look for different things, and their detection windows vary widely.
- Blood tests detect alcohol itself and are reliable for roughly 6 to 12 hours after your last drink, depending on how much you consumed.
- Breath tests (breathalyzers) can detect alcohol for up to 24 hours, though 12 to 16 hours is more typical for moderate drinking.
- Standard urine tests pick up alcohol for about 12 to 24 hours.
- EtG urine tests look for a metabolic byproduct rather than alcohol itself. After a few drinks, EtG can show up in urine for up to 48 hours. Heavier drinking can extend that window to 72 hours or longer.
- Hair tests can detect patterns of alcohol use for up to 90 days, though they reflect repeated consumption rather than a single episode.
The EtG test is worth knowing about specifically because it catches people off guard. It’s commonly used in workplace, legal, and treatment monitoring settings, and it’s sensitive enough to flag exposure days after the alcohol itself has left your bloodstream.
Why You May Still Feel Off After Alcohol Is Gone
Hangover symptoms often peak when your blood alcohol level returns to zero, not while you’re still intoxicated. This happens because your body is dealing with the aftereffects of processing alcohol: dehydration, inflammation, irritated stomach lining, and disrupted sleep architecture. You can feel foggy, nauseous, or headachy even though a breathalyzer would read 0.00. The fact that alcohol is no longer detectable doesn’t mean your body has fully recovered from its effects.
For most people, hangover symptoms resolve within 24 hours. But cognitive performance and reaction time can remain subtly impaired for longer than you’d expect, particularly after heavy drinking. Studies on next-day impairment consistently show measurable deficits in attention and coordination even when no alcohol remains in the blood.
The Bottom Line on Timing
For a single drink, your body needs about 60 to 90 minutes to process it completely. For a moderate evening of three to four drinks, expect four to six hours before your blood alcohol returns to zero. For heavier drinking, the math scales linearly: eight drinks means roughly eight to twelve hours. And if you’re concerned about testing, an EtG urine screen can flag alcohol use two to three days after your last drink, regardless of whether you “feel fine.”