How long does alcohol stay in your system?
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Your liver clears a fixed amount of alcohol an hour, so one US drink takes most adults about 2 to 3.5 hours to mostly leave the blood. Each drink before it adds more time. Count from your last drink, and give it longer than it feels.
Most people go by the rule of one drink an hour. It sounds right, because the buzz from a single drink fades in about that time. The alcohol in your blood takes about twice as long, and at one drink an hour the drinks stack up instead of clearing.
What we’d do
Plan on about 2 to 3.5 hours for each drink, more if you’re smaller, and start counting from your last drink. If you want the drinks gone by bedtime, finish earlier or have fewer, because nothing speeds up the liver once the alcohol is in. Don’t drive after drinking, whatever any clock says.
Why does it take so long?
Think of the liver as a store with one checkout lane. Once a drink or two is in, more drinks don’t go through faster. They wait in line.
The cashier is an enzyme called alcohol dehydrogenase. A 2010 forensic review of the published rates found it’s saturated after the first few drinks, so the level in your blood falls by about the same amount every hour. That’s 10 to 15 mg per 100 mL an hour on an empty stomach and 15 to 20 after eating, and 15 is a good average for moderate drinkers. When the level gets very low the enzyme slows down, so the last bit takes longer than simple division would say.
A US standard drink is 14 g of alcohol. In most bodies it pushes the level up by more than one hour of clearing, which is why a single drink takes 2 hours or more.
How long for 1, 2 or 4 drinks?
On our engine, with the drinks spread over the first hour and food not known, this is the time from the first sip until it’s mostly cleared. The range in brackets is the same evening for a liver at the fast and slow ends of the normal range.
| Body | 1 drink | 2 drinks | 4 drinks |
|---|---|---|---|
| Woman, 130 lb | 3.5 hours (2.7 to 5.1) | 6.7 hours | 12.6 hours |
| Woman, 160 lb | 2.9 hours (2.2 to 4.2) | 5.6 hours | 10.4 hours |
| Woman, 190 lb | 2.5 hours (1.9 to 3.6) | 4.8 hours | 8.9 hours |
| Man, 160 lb | 2.4 hours (1.9 to 3.4) | 4.6 hours | 8.6 hours |
| Man, 190 lb | 2.1 hours (1.6 to 2.9) | 4 hours | 7.4 hours |
| Man, 220 lb | 1.8 hours (1.5 to 2.6) | 3.6 hours | 6.5 hours |
Four drinks that start at 9pm are mostly cleared around 4:20am for a 190 lb man, 7:25am for a 160 lb woman and 9:35am for a 130 lb woman. For a lot of people, Friday night is still in their blood at breakfast.
Why is it longer for some people?
Alcohol spreads through the water in your body. Pound for pound, women have less of it than men, according to NIAAA, so the same drink at the same weight gives a higher level that lasts longer. Smaller bodies hold less water too.
Build changes it as well. In the published values collected in a 2015 review, the body water factor forensic scientists use runs from about 0.80 in a very lean man down to about 0.53 in a heavier woman. A meal before drinking lowers the peak and clears it sooner, which does eating before drinking help covers.
Can you speed it up?
No. NIAAA says cold showers, hot coffee and walking don’t reverse the effects of alcohol. Your level can even keep rising after your last drink, because alcohol still in your stomach and gut keeps entering your blood.
The calculator below draws your own evening with the one-drink-an-hour line beside it, so you can see the gap. It’s an average curve, and it’s never a test of whether you can drive.
When will it be out of my blood?
Out of your blood
Mostly cleared about 2:50am
That's 6.8 hours from your first sip, between 2:05am and 3:55am if your liver runs faster or slower than average. About 3.8 hours of your sleep overlap it.
This is an average curve. Your own level can be higher, and it can keep rising after your last drink. Never use it to decide whether you can drive.
The signs of an alcohol overdose
Call 911 right away if someone who has been drinking has any of these:
- Confusion or stupor
- Can't stay conscious, or can't be woken
- Vomiting
- Seizures
- Slow breathing, fewer than 8 breaths a minute
- Irregular breathing, 10 seconds or more between breaths
- Slow heart rate
- Clammy skin
- No gag reflex
- Very low body temperature
- Bluish skin or paleness
Don't leave them to sleep it off. Cold showers, hot coffee and walking don't reverse an overdose. NIAAA on alcohol overdose
18.9 g, 1.35 US drinksoz%- 18.9 g, 1.35 US drinksoz%
The dashed line is the myth. If your liver really cleared one US drink an hour, these drinks would be gone by 11pm. On an average liver they last until about 2:50am.
How long for N drinks?
4 US drinks spread over an hour, for your body: mostly cleared about 11 hours after the first sip (8.4 to 16.4 if your liver runs faster or slower). Started at 9pm, that's about 8:00am.
| US drinks | 1 | 2 | 3 | 4 | 6 | 8 |
|---|---|---|---|---|---|---|
| Hours from the first sip | 3.1 | 5.9 | 8.5 | 11 | 16.1 | 21.2 |
With Gyroscope One, snap or tap each drink and see what it did to your resting heart rate and sleep. How it works
For adults of legal drinking age, 21 in the US. If you're pregnant or trying, the CDC says there's no known safe amount of alcohol.
5 sources
- Jones AW, Evidence-based survey of the elimination rates of ethanol from blood with applications in forensic casework, Forensic Science International, 2010pubmed.ncbi.nlm.nih.gov
- Searle J, Alcohol calculations and their uncertainty, Medicine, Science and the Law, 2015pmc.ncbi.nlm.nih.gov
- National Institute on Alcohol Abuse and Alcoholism, What Is A Standard Drink? Updated December 2025niaaa.nih.gov
- National Institute on Alcohol Abuse and Alcoholism, Women and Alcohol, updated December 2025niaaa.nih.gov
- National Institute on Alcohol Abuse and Alcoholism, Understanding the Dangers of Alcohol Overdose, updated December 2025niaaa.nih.gov
