Your liver clears alcohol at a steady rate of about one standard drink per hour, and nothing speeds that up. After a night of drinking, the total time alcohol stays in your system depends on how much you consumed and which type of test is being used to detect it. A standard breathalyzer can pick up alcohol for up to 24 hours, while specialized urine tests can flag a metabolite of alcohol for 3 to 5 days after your last drink.
What Counts as One Drink
Before you can estimate how long alcohol will stay in your system, you need to know how many “standard drinks” you actually had. In the United States, one standard drink contains about 14 grams (0.6 fluid ounces) of pure alcohol. That equals:
- Beer: 12 ounces at 5% alcohol
- Wine: 5 ounces at 12% alcohol
- Liquor: 1.5 ounces (one shot) at 40% alcohol (80 proof)
A strong cocktail with two or three shots counts as two or three standard drinks, not one. A generous pour of wine in a large glass can easily be two drinks. Getting an honest count is the first step to estimating your timeline.
How Your Liver Processes Alcohol
Your liver does the vast majority of the work. It uses enzymes to convert ethanol into a toxic intermediate compound, then quickly converts that into a harmless substance your body can eliminate. This process runs at a fixed speed. Unlike many other substances, alcohol doesn’t clear faster just because there’s more of it in your blood. Your liver processes roughly one standard drink per hour regardless of how much you’ve consumed.
That means if you have five drinks between 8 p.m. and midnight, your liver needs approximately five more hours after your last drink to fully clear the alcohol. Time is the only thing that removes alcohol from your system.
Detection Windows by Test Type
Different tests look for different things, and their detection windows vary dramatically.
Breath: A breathalyzer can detect alcohol for up to 24 hours after drinking. This is the test used in roadside stops and workplace screenings.
Blood: Alcohol shows up in a blood test for up to 12 hours. Blood tests give the most precise measurement of current impairment.
Urine (standard): A traditional urine test detects alcohol for 10 to 12 hours after your last drink.
Urine (EtG): This is the one that catches people off guard. The EtG test doesn’t look for alcohol itself. It looks for a byproduct your body creates while processing alcohol. After a few drinks, this metabolite can show up in urine for up to 48 hours. With heavier drinking, it can be detected for 72 hours or longer. Courts, probation programs, and some employers use EtG testing specifically because of this extended window. However, a positive EtG result doesn’t mean you’re currently impaired.
What Affects How Fast You Metabolize Alcohol
While one drink per hour is the average, individual variation is real. Your genetics play a significant role. The enzymes responsible for breaking down alcohol come in different variants across populations, and some people produce more active versions than others. This is one reason why alcohol hits some people harder or clears more slowly.
Body size matters because alcohol distributes through your body’s water content. A smaller person reaches a higher blood alcohol concentration from the same number of drinks as a larger person. Biological sex plays into this as well: women generally have a higher proportion of body fat and less body water than men of the same weight, which means alcohol concentrates more in their blood. Age slows metabolism in general, and alcohol processing is no exception. Liver health is another factor. If your liver is already under strain from chronic heavy drinking or other conditions, it won’t clear alcohol as efficiently.
Food also changes the equation, though it affects absorption rather than metabolism. Drinking on an empty stomach causes alcohol to hit your bloodstream fast, with peak levels sometimes arriving within about 40 minutes. Eating a meal before drinking slows absorption and produces a lower, more gradual peak, typically around 22 minutes after finishing the drink but at a much reduced intensity. The total amount of alcohol your body needs to process stays the same, but food prevents the sharp spike that leads to rapid intoxication.
Why Coffee and Water Don’t Help
This is one of the most persistent misconceptions about sobering up. Coffee, cold showers, energy drinks, and water do not speed up alcohol metabolism. The CDC is clear on this point: caffeine mixed with alcohol does not reduce alcohol’s effects on your body. Coffee might make you feel more alert, but your blood alcohol level stays exactly the same. You become a wide-awake drunk rather than a sleepy one, which can actually be more dangerous because it masks how impaired you really are.
Hydration is good for reducing hangover symptoms, but it doesn’t help your liver work any faster. The only reliable way to lower your blood alcohol level is to wait.
BAC Levels and What They Mean
Your blood alcohol concentration (BAC) determines both your level of impairment and how long until you’re fully sober. In most U.S. states, the legal driving limit is 0.08%. But impairment starts well below that threshold.
At a BAC between 0.16% and 0.30%, you’ll have serious difficulty walking and speaking. Memory blackouts, vomiting, and loss of consciousness can occur in this range. Above 0.31%, the situation becomes life-threatening. Breathing can slow dangerously, and coma or death is possible. These aren’t extreme edge cases reserved for binge drinkers with unusual tolerance. A person of average size who drinks heavily over a short period can reach these levels.
Practical Timeline Estimates
Here’s a rough guide based on the one-drink-per-hour rule. If you stop drinking at midnight after consuming four standard drinks (say, four shots of liquor), your liver needs approximately four hours to clear all the alcohol. That puts you at roughly 4 a.m. before your BAC reaches zero. If you had eight drinks, you’re looking at around 8 a.m.
Keep in mind these are estimates for a person of average size with normal liver function. They also assume you stopped drinking at a specific time. Your body doesn’t start a countdown from your last sip. It’s been metabolizing alcohol the entire time you were drinking, so the math is slightly more forgiving than it sounds. Still, many people underestimate how long it takes. Someone who drinks heavily until 2 a.m. and drives to work at 7 a.m. may still have a measurable BAC.
For drug testing purposes, the timeline is longer. If you have a standard urine test, plan on at least 12 hours. For an EtG test, even moderate drinking can produce a positive result two to three days later.