How long does alcohol stay in your system? For most people, blood alcohol falls by roughly 0.015 percentage points per hour after absorption is complete. At that average rate, a blood alcohol concentration (BAC) of 0.08% takes around five to six hours to return to zero, and a higher peak takes longer. Tests can detect alcohol or its byproducts for longer still.
These are averages, not a personal countdown. This guide explains how the timeline works, why it varies, why the "next morning" is often riskier than people expect, and why no calculation can tell you when it is safe to drive.
How long does alcohol stay in your system after drinking?
Alcohol moves through three stages:
- Absorption. Alcohol passes from the stomach and small intestine into the blood. BAC usually peaks somewhere between 30 and 90 minutes after the last drink, and later after a large meal.
- Elimination. The liver breaks down most alcohol at a fairly steady rate. A small amount leaves in breath, sweat, and urine.
- Byproducts. Even after alcohol itself is gone, the body may still contain metabolites that some tests look for.
Because elimination is roughly constant, the time to clear alcohol depends mainly on how high BAC got. Drinking more does not speed up the liver; it just extends the time.
How long until BAC returns to zero?
The table below applies the commonly quoted average of 0.015 per hour from the time BAC peaks. Real rates vary between people, so read this as an illustration only.
| Peak BAC | Approximate hours to reach zero at 0.015 per hour |
|---|---|
| 0.02% | 1.3 |
| 0.05% | 3.3 |
| 0.08% | 5.3 |
| 0.10% | 6.7 |
| 0.15% | 10 |
| 0.20% | 13.3 |
Two things stand out. A heavy night can leave alcohol in the blood well into the next day. And the hours start counting from the peak, not from your first drink, so a late final round pushes everything later.
How long does it take for one drink to leave your system?
A common rule of thumb is that the body clears about one standard drink per hour on average. A 12 oz beer at 5%, a 5 oz glass of wine at 12%, and a 1.5 oz shot of 40% spirits are each one U.S. standard drink. Larger or stronger drinks take longer. See how many drinks per hour your body can process for why this rule is only approximate.
What affects how long alcohol stays in your system?
Two people who drink the same amount can have different BAC levels and different clearance times. Major factors include:
- How much you drank. This matters most. More alcohol means a higher peak and a longer elimination period.
- How fast you drank. Drinking quickly produces a higher peak.
- Body weight and composition. Alcohol distributes through body water, so smaller bodies and bodies with less water generally reach a higher BAC from the same amount.
- Sex. On average, women reach higher BAC than men after the same number of drinks, partly due to differences in body water.
- Food. Eating slows absorption and lowers the peak. It does not speed elimination.
- Genetics, liver health, and medications. These can change the elimination rate or interact dangerously with alcohol.
Because so many variables are involved, a BAC calculator can only offer an educational estimate. It cannot measure your actual BAC.
How long can tests detect alcohol?
Detection windows depend on the test and on how much was consumed:
- Breath and blood tests measure alcohol that is still in the body, so they generally become negative once BAC returns to zero. After heavy drinking that can be many hours.
- Urine tests for alcohol itself work over a similar window to blood, but ethyl glucuronide (EtG) tests, which look for a byproduct of alcohol, can detect drinking for a day or several days afterward, especially after heavy drinking.
- Hair tests can show patterns of alcohol use over months.
If you have a test for work, legal, or medical reasons, ask the testing provider what they measure and follow their guidance. Do not rely on an online estimate.
Is it safe to drive the next morning?
Not necessarily. Many drivers who are stopped for alcohol the morning after did not feel drunk. If you drank heavily until late at night, alcohol can still be in your blood after a few hours of sleep.
Consider an example. If someone's BAC peaks at 0.15% at 1 a.m., the average rate suggests it would take until around 11 a.m. to reach zero. Their individual rate could be slower. Feeling rested or alert does not tell you your BAC.
Safer choices include:
- Planning transport for the next morning as well as the night itself.
- Stopping drinking well before you need to drive, with a large margin.
- Choosing not to drink when you need to drive early the next day.
For more on this, see the drink-drive calculator safety guide.
Myths about sobering up faster
None of the following lowers BAC faster than the liver can clear it:
| Myth | What actually happens |
|---|---|
| Coffee sobers you up | Caffeine may make you feel more alert but does not lower BAC |
| A cold shower helps | It may make you feel awake; BAC is unchanged |
| Exercise "sweats it out" | Very little alcohol leaves through sweat |
| Eating a big meal afterward | Food slows absorption of alcohol still in your stomach but does not clear what is in your blood |
| Sleeping it off is enough | Sleep passes time, but the amount of time needed may be longer than the night |
| Drinking water flushes it out | Water helps hydration, not elimination |
Only time reduces BAC.
When to get help
If someone has been drinking and is confused, vomiting repeatedly, having seizures, breathing slowly or irregularly, has blue-tinged or pale skin, or cannot be woken, these can be signs of alcohol poisoning. Call emergency services (911 in the U.S., 999 in the UK). Do not leave them alone or let them "sleep it off."
Understand your own patterns
Knowing how long alcohol stays in your system is most useful when you also know how much you actually drink. Many people underestimate both the size of their drinks and how late in the evening they finish.
Alcohol Tracker° records each drink with a timestamp, size, and strength, so you can review an evening afterward and see your totals by day and week. You can [see how Alcohol Tracker° works](/) or read about practical ways to reduce alcohol intake.
Frequently Asked Questions
How long does it take for alcohol to leave your system after 4 drinks?
It depends on your body and how quickly you drank, but at the common average of one standard drink per hour, four standard drinks take roughly four hours or more to clear after absorption. Many people take longer. Do not use this estimate to decide whether to drive.
How long does alcohol stay in your blood?
Alcohol stays in the blood until the liver has cleared it. At the commonly quoted average of 0.015 per hour, a BAC of 0.08% takes about five to six hours to reach zero, and higher levels take longer.
How long does alcohol stay in your urine?
Standard urine alcohol tests detect alcohol over a similar window to blood. EtG tests look for an alcohol byproduct and can detect drinking for a day or several days afterward, depending on the amount consumed.
Does sleeping make alcohol leave your system faster?
No. Sleep does not change the elimination rate. It simply lets time pass, and after heavy drinking a night's sleep may not be long enough for BAC to return to zero.
Is there a calculator for how long alcohol stays in your system?
BAC calculators estimate how BAC might change over time, but they cannot account for every personal factor. Treat any result as education only. A calculator cannot tell you that it is safe to drive.
The quick answer
How long does alcohol stay in your system? On average, BAC falls by about 0.015 per hour, so a BAC of 0.08% takes around five to six hours to clear and heavier drinking can last into the next day. Rates vary, nothing speeds the process up, and tests may detect alcohol byproducts for longer. Plan transport, and never rely on an estimate to drive.
Sources: NIAAA: Understanding the dangers of alcohol overdose, CDC: Impaired driving facts, and NHS: Alcohol poisoning.
Keep exploring
Use the calculator or continue with a related guide:
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