How Long Does Alcohol Stay in Your System?
Alcohol leaves your blood at roughly 0.015 % BAC per hour, about one standard drink an hour. Tests keep score for much longer: a breathalyzer can pick it up for up to 24 hours, urine tests for 12–72 hours, hair tests for up to 90 days. Your own timing, though, comes down to your weight, your sex and what you actually drank. Not to the averages.
How your body clears alcohol
Your liver does almost all the work, and it works at a fixed pace. No shortcut changes that. What varies is the peak: how high your curve climbs before it starts to fade.
So two people who drank the same things on the same evening can end up hours apart on the way down. The descent runs at the same steady rate for both of them. The difference is where it starts, and a higher peak simply means a longer way to fall.
How long until you feel sober — and why that's not zero
Feeling sober and testing sober run on two different clocks. Most people feel fine hours before their BAC actually reaches 0.00. That gap is where guessing goes wrong.
Can you still be drunk 8 hours later? If the peak was high enough, yes. Sleep doesn't speed the liver up. After a big night the curve can still sit above zero well into the next morning.
Detection windows by test type
One beer and a long evening are different stories. Detection scales with how far your curve had to fade before the test. Typical windows are below; your own numbers depend on how much you drank and on your body.
| Test | Typical window |
|---|---|
| Breathalyzer | up to 24 h |
| Urine test | 12–72 h |
| Blood test | up to ~12 h |
| Hair test | up to 90 days |
| Standard drug-test panels | depends on the panel |
Breathalyzer
A breathalyzer reads the alcohol still in your blood through your breath. It only shows a number while your BAC is above zero. For most evenings that means a few hours. After a heavy one it can stretch toward a full day.
Urine test
Urine tests look for what alcohol leaves behind, metabolites like EtG, so they keep reporting long after you're back at 0.0. One drink sits near the bottom of the range. A long evening pushes it toward the top.
Blood test
A blood test measures actual BAC, the same value your curve shows. It clears at your elimination pace, roughly one standard drink per hour. Even a big evening is usually out of the blood within half a day.
Hair test
Hair keeps a long archive. Markers of drinking can be read there for up to three months. That's a story about past weeks, not about tonight — and no timing trick touches it.
Standard drug-test panels
Panels differ. Some read blood, others urine, and a few add EtG on top. Whatever the underlying test is, that's your window: if you know which panel you're facing, the rows above already answer it.
When will you be at zero?
Averages answer for a textbook body. Enter yours instead: weight, sex, drinks, time. You'll get your curve, your peak, and the hour it fades to zero.
The curve shows how alcohol builds up and fades in your blood — drink by drink, tuned to your weight, sex, and pace. You’ll see the peak, when it hits, and when you’re back to zero.
This calculator provides a rough estimate based on the Widmark formula. Actual BAC depends on many factors including metabolism, food intake, medications, and individual physiology. Never drive or operate machinery based on a calculator estimate.
Can you speed it up?
Coffee, cold showers, water, greasy food. People try all of it. Only time actually moves your BAC, and here's what each trick really does instead.
The one thing that works is time. Your curve fades at a steady pace, so the useful move is knowing that hour instead of guessing it.
Frequently Asked Questions
How long does it take alcohol to fully leave your body?
At a typical elimination pace your BAC drops by about one standard drink per hour. A couple of drinks are gone in a few hours. A long evening can take 8–12 hours to reach true zero, and urine tests can still register leftovers for up to three days after that.
Can you still be drunk 8 hours later?
Yes, if your peak was high. BAC falls at a fixed rate, so a late, heavy evening can still be above zero the next morning. Feeling awake doesn't mean the curve is done fading.
How long does it take to get to 0.00 after one drink?
One standard drink is typically gone in about one to two hours, depending on your weight and sex. The clock starts when you finish the drink, not when you order it.
What is your BAC after 1 beer?
For most adults one 330 ml (12-oz) beer peaks somewhere around 0.01–0.03 % BAC (0.1–0.3 ‰), highest about 30–60 minutes after finishing. Run your numbers in the widget above to see your own peak instead of the average.
Can you flush alcohol out of your system with water?
No. Water is good for how you'll feel tomorrow, but it doesn't speed your liver up: BAC falls at the same fixed pace. Every “flush” trick fails for the same reason. Only time moves the curve down.
How long does a unit of alcohol take to leave the body?
About one hour per unit (8 g of pure alcohol) for most people. A pint of beer is two to three units, a small glass of wine about one and a half. Your weight and sex shift that pace, which is why a personal curve beats the per-unit rule of thumb.