Guides
How long does alcohol stay in your system by body and by test
Alcohol leaves the body at a fairly steady pace, and almost nothing you do speeds it up. How long it stays in your system depends on how much you drank, your body and the kind of test someone uses to look for it. A breath or blood test looks for alcohol itself and stops finding it within hours, while some urine and hair tests look for traces the body leaves behind and can reach back days or even months. This guide explains how the body processes alcohol, the typical ranges for each test, the factors that change the timing, and the myths that do not work.
- Last drink, food, smoke or rinseThe clock starts here
- Mouth alcohol clearsAt least 15 minutes, longer if the manual asks
- Blow one steady breathDeep lung air is what the sensor should read
How the body breaks down alcohol
After a drink, alcohol is absorbed through the stomach and mostly through the small intestine into the bloodstream. Blood alcohol keeps rising while absorption continues, usually reaching its peak somewhere between 30 and 90 minutes after the last drink, later if you ate a full meal.
The liver does most of the clearing. An enzyme called alcohol dehydrogenase converts alcohol into acetaldehyde, a toxic compound, and a second enzyme turns acetaldehyde into acetate, which the body breaks down further into water and carbon dioxide. A small share of alcohol leaves unchanged through breath, urine and sweat, which is why breath testing works at all.
The liver works at a roughly fixed pace. Drinking more does not make it work faster, it only makes the queue longer.
The average elimination rate
For most adults, blood alcohol concentration falls by about 0.015 per hour once absorption is complete. Published research reports a typical range of roughly 0.010 to 0.020 per hour, and some people fall outside it. At the average rate, a peak of 0.08 takes a little over five hours to reach zero, and a peak of 0.15 takes about ten hours.
That arithmetic is why the morning after a heavy night is a common time for people to still be impaired without feeling it. Our BAC calculator applies this rate to give a rough timeline, and the BAC chart shows typical levels by drinks and body weight.
This is an estimate. It cannot tell you whether you are safe or legal to drive. If you have been drinking, do not drive.
Detection windows by type of test
Each test looks for something different, so each has its own window. The ranges below are typical figures from published research and testing guidance, not guarantees for any one person.
| Test | What it detects | Typical window |
|---|---|---|
| Breath | Alcohol in exhaled air | While alcohol is in the blood, usually up to about 12 to 24 hours after heavy drinking |
| Blood | Alcohol in the bloodstream | Similar to breath, usually up to about 12 to 24 hours |
| Saliva | Alcohol in the mouth and saliva | Usually up to about 12 to 24 hours |
| Urine, standard | Alcohol itself | Usually up to about 12 to 24 hours |
| Urine, EtG or EtS | Breakdown markers of alcohol | Up to about 80 hours after heavy drinking |
| Hair | EtG stored in the hair shaft | Up to about 90 days |
Breath and blood tests are what police, employers under federal rules and interlock devices rely on, because they measure alcohol in the body right now. EtG urine tests and hair tests are used in monitoring programs, some courts and treatment settings, because they show whether someone has been drinking recently rather than how impaired they are at the moment. A low level of drinking or contact with alcohol based products can sometimes show up in sensitive EtG tests, which is why labs and programs set their own cutoffs.
To learn how breath testing itself works, read our breathalyzer test guide.
What changes how long alcohol stays in your body
The average rate is a middle point. Several factors move individual timing up or down.
- How much and how fast you drank. More alcohol means more time, and drinking quickly raises the peak.
- Body weight and composition. Alcohol spreads through body water, so a smaller body or a higher share of body fat leads to a higher concentration from the same drink.
- Sex. On average women reach a higher BAC from the same amount of alcohol, mainly because of differences in body water.
- Food. A meal slows absorption and lowers the peak, but it does not speed elimination once alcohol is in the blood.
- Age and liver health. Liver disease and age related changes can slow clearing.
- Medications. Some medicines interact with alcohol or with the enzymes that process it.
- Drinking history. Regular heavy drinkers can clear alcohol somewhat faster, but they also carry other health risks, and tolerance does not lower the BAC a test reads.
- Drink strength. Craft beers, large pours and mixed drinks often hold more than one standard drink.
Myths about sobering up faster
Many tricks are said to clear alcohol quickly. None of them changes how fast the liver works.
- Coffee. Caffeine can make you feel more alert, but your BAC stays the same, and an alert person who is still impaired may take more risks.
- A cold shower. It may wake you up, but it does nothing to the alcohol in your blood.
- Exercise and sweating. Only a tiny share of alcohol leaves through sweat, far too little to matter.
- Drinking water. Water helps with dehydration, not with the rate of elimination.
- Eating after drinking. Food slows absorption of alcohol still in the stomach, but it does not remove what is already in the blood.
- Sleeping for a few hours. Sleep passes time, which is the only thing that works, but a short sleep after a heavy night is often not enough time.
Breath fresheners and mouthwash do not lower your BAC either, and some contain alcohol that can raise a breath reading for a while. A personal tester does not help you get around any of this; it only gives you an estimate.
Checking your level the next morning
If you want a number before you decide how to get to work the next day, a personal breathalyzer gives a better estimate than guessing from the clock. A fuel cell model is the most reliable choice for this use, because the sensor responds to alcohol specifically. Wait at least 15 minutes after eating, drinking, smoking or using mouthwash before you blow, and if the reading shows any alcohol, treat it as a reason not to drive.
Start with our best breathalyzer ranking, or compare fuel cell breathalyzer models. The state by state rules are on our legal limit page.
When alcohol becomes an emergency
A very high BAC can stop breathing and other vital functions. If someone is confused, vomiting while drowsy, breathing slowly or irregularly, has pale or bluish skin or cannot be woken, call 911. Do not leave them alone, and do not wait for the alcohol to wear off.
Questions about alcohol in your system
How long does it take for one drink to leave your system?
For most adults the body clears roughly one standard drink in about an hour to an hour and a half, though weight, sex and food change this.
How fast does BAC go down?
On average it falls by about 0.015 per hour once absorption is complete, with a typical range of roughly 0.010 to 0.020 per hour.
How long can a urine test detect alcohol?
A standard urine test usually finds alcohol for up to about 12 to 24 hours, while an EtG test can detect breakdown markers for up to about 80 hours after heavy drinking.
Can a hair test show alcohol use?
Yes, hair tests look for EtG stored in the hair and can reflect drinking over roughly the last 90 days.
Does coffee or a cold shower sober you up?
No, they may make you feel more awake, but only time lowers your blood alcohol concentration.
Can I still be over the limit the morning after drinking?
Yes, after a heavy night your BAC can still be above zero or above the limit the next morning, so check before you drive and do not drive if you have any doubt.