How Long Does Alcohol Stay in Your System? Blood, Breath, Urine and Hair — The Real Numbers

Type this question into a search engine and you'll get a hundred different answers, because there isn't one number — there are five. Alcohol leaves your blood in hours, your breath in up to a day, your urine in up to three days (or five, with the right test), your saliva in up to two days, and your hair holds the record for ninety days. Which number matters depends on why you're asking. This article gives you all five, the math your liver actually uses, and the honest answer to the question underneath the question — because almost nobody googles this out of pure curiosity.

The short answer, test by test

Your body eliminates alcohol at a nearly fixed rate, but different tests can see it for very different lengths of time:

• Blood — up to 12 hours after your last drink. Blood tests measure active alcohol (your actual BAC), so once your liver finishes the job, the test reads zero.
• Breath (breathalyzer) — 12 to 24 hours. Breath alcohol mirrors blood alcohol, so the window depends entirely on how much you drank and when you stopped.
• Urine (standard test) — 12 to 72 hours. Standard urine tests detect alcohol itself and its immediate breakdown products.
• Urine (EtG test) — up to 80 hours, sometimes longer after heavy drinking. EtG (ethyl glucuronide) is a metabolite that lingers long after the alcohol is gone — this is the test used in court-ordered monitoring and many workplace programs.
• Saliva — 12 to 48 hours. Roughly tracks blood alcohol with a slightly longer tail.
• Hair follicle — up to 90 days. Hair tests don't measure intoxication at all; they record a months-long history of drinking patterns.

Notice the pattern: the tests that matter for being impaired (blood, breath) clear fast. The tests that matter for proving abstinence (EtG, hair) see much, much further back. People are routinely surprised by EtG — you can feel completely sober on Monday morning and still test positive for Saturday night.

The math your liver actually uses

Alcohol elimination is one of the most predictable processes in your body, and the math is simple enough to do in your head.

Your liver clears alcohol at a fixed rate of roughly 0.015 BAC per hour — about one standard drink per hour, no matter how many drinks are waiting in line. Unlike most drugs, alcohol metabolism doesn't speed up when there's more of it. The enzyme that does the work, alcohol dehydrogenase, runs at full capacity from the first drink. Everything else queues.

A standard drink is smaller than most people pour:

• 355 ml (12 oz) of 5% beer
• 150 ml (5 oz) of 12% wine — most restaurant pours are closer to two standard drinks
• 44 ml (1.5 oz) of 40% spirits — a generous home pour is often double

Now the math. If your BAC peaks at 0.08% — the legal driving limit in much of the world, typically reached after roughly 4 drinks in 2 hours for a 70 kg man, fewer for most women — your liver needs about 5 to 6 hours to get back to zero. A heavy night that peaks at 0.20% needs 13+ hours. That's why "I slept it off" so often fails a morning breathalyzer: if you stopped drinking at 2 AM with a 0.18% BAC, you're still legally impaired at 9 AM, coffee or no coffee.

Three rules of thumb worth memorizing:

• One standard drink ≈ one hour to leave your blood.
• A bottle of wine ≈ 10 hours.
• BAC of 0.08% at bedtime ≈ sober around sunrise. BAC of 0.16% ≈ not until lunch.

What changes the timeline (and what doesn't)

The elimination rate is nearly fixed, but your peak BAC — and therefore the total time — varies enormously from person to person:

• Body weight and composition. Alcohol distributes through body water. A smaller person, or a person with higher body fat, reaches a higher BAC from the same drinks.
• Sex. Women typically have less body water per kilogram and lower levels of stomach alcohol dehydrogenase, so the same drinks produce a 20–30% higher BAC on average.
• Food. Drinking on a full stomach can cut peak BAC by up to a third by slowing absorption. It doesn't speed elimination — it just flattens the peak.
• Age. Body water decreases with age, so the same drinks hit harder at 60 than at 25.
• Liver health. A damaged liver clears alcohol more slowly. Heavy long-term drinkers often have induced enzymes that work slightly faster — until the liver scars, and then dramatically slower.
• Medications. Some common drugs (certain antibiotics, H2 blockers, and others) interfere with alcohol metabolism. Check the label, every time.
• Genetics. Variants in the ADH and ALDH genes — most common in East Asian populations — change how fast alcohol and its toxic intermediate, acetaldehyde, are processed.

And here is the part every honest article has to say plainly: nothing speeds it up. Not coffee — that makes a wide-awake drunk. Not a cold shower — that makes a wet one. Not sweating it out at the gym — less than 10% of alcohol leaves through sweat, breath, and urine combined; the other 90%+ goes through the liver at its fixed, stubborn rate. Not water — hydration helps the hangover, not the BAC. The only thing that removes alcohol from your system is time. Every shortcut you've heard of is folklore.

Why EtG tests catch what breathalyzers miss

This deserves its own section because it's the single most-searched confusion on this topic.

When your liver breaks down alcohol, a tiny fraction gets converted into ethyl glucuronide (EtG) and ethyl sulfate (EtS) — stable metabolites that your kidneys excrete slowly over days. A breathalyzer asks "is there alcohol in your blood right now?" An EtG test asks "has alcohol been through this body in the last three days?"

The practical numbers, from clinical monitoring research:

• Light drinking (1–2 drinks): EtG detectable for roughly 24 hours.
• Moderate drinking (4–5 drinks): roughly 48 hours.
• Heavy drinking: up to 72–80 hours, occasionally longer.

EtG tests are sensitive enough to occasionally flag heavy use of alcohol-based hand sanitizer or mouthwash — which is why monitoring programs usually pair them with EtS and set cutoff thresholds. But for ordinary purposes the rule is simple: if you drank meaningfully within the last three days, assume an EtG test will know.

The question underneath the question

Here's something worth saying without judgment: people don't usually google "how long does alcohol stay in my system" once. They google it on Sunday night before a Monday drug screen. They google it at 6 AM doing math about the morning commute. They google it before a doctor's appointment, a custody hearing, a new job's onboarding.

If you've searched this more than a couple of times, the searches themselves are data. Not proof of a problem — data. The clinical research on alcohol use disorder is clear that one of the earliest, quietest signs is organizing logistics around drinking: counting hours, timing tests, planning mornings around the night before.

There's a simple, zero-commitment experiment that thousands of people run: track the days instead of the hours. Sober Tracker is a free, private, no-account app that counts your alcohol-free days and shows you what your body does with each one — the first 30 days are a measurable, hour-by-hour repair sequence. If the streak is easy, great — you've learned your relationship with alcohol is casual. If the streak is surprisingly hard, you've learned something more important, for free, in private.

What your body does once the alcohol is gone

Zero BAC is not the finish line — it's the starting gun. Once the last drink clears:

• Within 24 hours, blood sugar regulation and hydration begin normalizing.
• Within 72 hours, the acute withdrawal window closes for most people (heavy daily drinkers: this window needs medical supervision — see below).
• Within 1–2 weeks, sleep architecture starts rebuilding — though the first nights are often rough, and that's normal.
• Within 2–4 weeks, cravings peak and begin to fade, liver fat starts measurably decreasing, and blood pressure begins to drop.

The detection windows in this article measure how long alcohol lingers. The recovery timeline measures how long its absence takes to pay you back. The second number is the one worth tracking.

When this stops being a math problem

Get medical help rather than waiting it out if:

• You drink daily or near-daily and want to stop — abrupt withdrawal from heavy daily drinking can cause seizures and can be fatal. A medically supervised taper is safe and standard.
• You've had shakes, sweats, or anxiety relieved by a morning drink.
• You're doing BAC math before driving more than rarely.
• You've failed a test you planned around.

The NIAAA Treatment Navigator is a good starting point in the US. None of this is failure. It's the same math, applied to a longer timeline.

Sober Tracker FAQ

How long after drinking can I drive?

Count your standard drinks and allow at least one hour per drink from your last drink, then add a margin. After a heavy night (6+ drinks), assume you are not legal to drive before mid-morning — possibly later. A cheap personal breathalyzer beats arithmetic; arithmetic beats optimism.

Does beer leave your system faster than liquor?

No. A standard beer, a glass of wine, and a shot of spirits contain roughly the same alcohol and take roughly the same hour to clear. Beer is absorbed slightly more slowly, which lowers the peak — but total elimination time depends only on total alcohol.

Will one drink show up on a test?

On a blood or breath test: only for a few hours. On a standard urine test: up to ~12–24 hours. On an EtG test: up to ~24 hours. On a hair test: a single drink rarely registers — hair tests are designed to detect patterns, not events.

Can I sweat out alcohol with exercise?

No. Under 10% of alcohol leaves through sweat, breath, and urine combined. Exercise doesn't accelerate the liver. It can, however, dehydrate you and make the hangover worse.

How long does alcohol stay in breast milk?

Breast milk alcohol tracks blood alcohol almost exactly — about one drink ≈ two hours until the milk is clear, two drinks ≈ four to five hours. "Pump and dump" doesn't speed it up; only time clears it. The CDC and most pediatric bodies publish per-drink waiting tables worth checking.

The honest takeaway

Alcohol leaves your blood at about one drink per hour, your urine within three days, and your hair within three months — and nothing you can drink, sweat, or buy changes those numbers. The math is fixed. The only variable you control is the input.

Most people who land on this article needed one number for one morning. But if you've noticed yourself needing the number more often, that pattern is worth more attention than the number itself. Tracking days instead of hours is the cheapest diagnostic there is — Sober Tracker is free on the App Store and Google Play, private, and takes ten seconds a day.

Your liver does the same hour of work whether you're counting or not. Counting is how you find out whether you want to give it less to do.

Sources cited

• NIAAA — Alcohol Metabolism: An Update, Alcohol Alert No. 72
• Cederbaum AI — Alcohol Metabolism, Clinics in Liver Disease, 2012
• Jones AW — Evidence-Based Survey of the Elimination Rates of Ethanol from Blood, Forensic Science International, 2010
• Helander A, Böttcher M et al. — Detection Times for Urinary Ethyl Glucuronide and Ethyl Sulfate in Heavy Drinkers during Alcohol Detoxification, Alcohol and Alcoholism, 2009
• NHTSA — Alcohol and Driving: Computing a BAC Estimate
• CDC — Alcohol and Breastfeeding: Frequently Asked Questions
• NIAAA — What Is a Standard Drink? and Alcohol Use Disorder and Treatment Navigator

This article is not medical advice. If you're concerned about alcohol withdrawal symptoms — especially shakes, hallucinations, or seizures — seek medical care immediately. The NIAAA Treatment Navigator is a good starting point in the US.