The honest answer depends on what you're testing. Your blood clears alcohol in a matter of hours. Your breath follows a similar timeline. But urine, saliva, and hair tests can pick up evidence of drinking for anywhere from a day to several months, depending on the test. This guide breaks down each one in plain terms, so you know what to actually expect.
Used to estimate body water distribution — the biggest factor in BAC accuracy.
Average is 0.015%/hr. Genetics, liver health, and tolerance shift this between 0.010–0.020%/hr.
Log each drink as you go for the most accurate live curve.
Modeled absorption & elimination curve for your full session.
0 / 8 glasses
Water helps prevent dehydration and eases next-day symptoms, but it does not lower your BAC or speed up alcohol metabolism. Only time does that.
General effects by approximate BAC level. Individual response varies significantly.
| BAC | Typical Effects |
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Your liver breaks down alcohol at a fairly fixed rate, roughly one standard drink per hour, regardless of how much you’ve had or how fast you drank it. That rate doesn’t speed up no matter what you try. Based on that, here’s a rough overview of how long alcohol is detectable across the most common test types:
This is the number most people actually care about, since it’s what a breathalyzer or blood alcohol content (BAC) reading is based on.
On average, the body eliminates alcohol at a rate of about 0.015% BAC per hour. So if your BAC is 0.08%, the legal driving limit in most US states, it takes roughly five to six hours to get back down to 0.00%. A heavier drinking session, say a BAC of 0.15% or higher, can take ten hours or more to fully clear.
There is no way to speed this up. Coffee, cold showers, exercise, and greasy food don’t make your liver work any faster. The only thing that lowers your BAC is time.
If you want an actual number based on your own weight, sex, and what you drank, rather than a rough average, our free BAC calculator gives you a live estimate, including how long until you’re back under the legal limit or fully sober.
Breath tests measure alcohol vapor that transfers from your blood into your lungs, so the timeline closely tracks your blood alcohol level. As a general rule, alcohol is detectable on your breath for as long as it’s still measurable in your blood, and sometimes slightly longer, up to 12 to 24 hours after heavy drinking, since trace amounts can linger even after your BAC reads close to zero.
This is why “I only had a few drinks last night” doesn’t always hold up the next morning. If you drank late and heavily, you can still register a measurable BAC well into the following day.
Urine tests come in two main types, and the difference in detection windows is significant.
Standard urine alcohol test: Detects alcohol for roughly 12 to 48 hours after your last drink, depending on how much you consumed.
EtG (ethyl glucuronide) test: This is a more sensitive test that looks for a byproduct of alcohol metabolism rather than alcohol itself. It can detect alcohol use up to 72 to 80 hours after drinking, sometimes longer in heavy drinkers. EtG tests are commonly used in legal, medical, and workplace monitoring situations specifically because of this longer window.
Saliva tests are less common but are sometimes used for quick screening. Alcohol is generally detectable in saliva for around 12 to 24 hours after drinking, similar to breath testing, though the exact window can vary by test sensitivity.
Hair follicle testing works completely differently from the others. Instead of detecting alcohol itself, it detects a chemical marker your body produces after metabolizing alcohol, which becomes embedded in the hair shaft as it grows.
Because hair grows slowly and steadily, this test can detect alcohol use going back up to 90 days. It’s not used to check whether someone had a drink last night, it’s used to establish a longer-term pattern of alcohol use, which is why it shows up mostly in legal and medical monitoring contexts rather than everyday testing.
The ranges above are averages. Your actual numbers can shift based on:
No. Water can help with dehydration and may ease some symptoms of drinking, but it does not speed up how quickly your liver metabolizes alcohol. The same goes for coffee, exercise, and sleep. None of them change your elimination rate. The only real variable is time.
The only way to know your real blood alcohol content is through a calibrated breathalyzer or an actual blood test. That said, a BAC calculator can give you a solid estimate based on your weight, sex, what you drank, and how much time has passed, which is useful for understanding roughly where you stand.
Use our free BAC calculator to estimate your current blood alcohol content, see how long until you’re under the legal limit, and know approximately when you’ll be fully sober.
QUESTIONS
A standard urine test can detect alcohol for 12 to 48 hours. A more sensitive EtG test can detect it for up to 72 to 80 hours, sometimes longer after heavy drinking.
On average, BAC drops by about 0.015% per hour. A BAC of 0.08% takes roughly five to six hours to reach zero. Higher BAC levels take proportionally longer.
Yes. If you drank heavily or late at night, your BAC may still be well above zero the next morning. Many DUI arrests happen the morning after a night of drinking, not the night of.
Eating slows how quickly alcohol enters your bloodstream, which can lower your peak BAC, but it does not change how long your liver takes to fully break down the alcohol already in your system.
Up to about 90 days. Hair testing is used to identify long-term drinking patterns rather than a single recent drink.
No. Coffee, cold showers, exercise, and food do not speed up how fast your liver processes alcohol. Time is the only factor that lowers BAC.
They give a solid estimate based on standard formulas and averages, generally within 15 to 20% of an actual breath or blood test. For certified results, only a calibrated breathalyzer or professional blood test is reliable.