How Long Does Alcohol Stay in Your System? The Honest Ranges

Quick answer: Your body clears alcohol at a fixed, fairly slow rate — the published range is 10 to 35 mg per 100 mL of blood per hour, with about 15 mg the typical figure for moderate drinkers. Ethanol itself is usually undetectable in blood 10 to 12 hours after the last drink. Tests that look for alcohol's metabolites run far longer: urine EtG up to about 130 hours after heavy drinking, blood PEth up to 12 days, hair EtG for months. Nothing you do speeds any of it up.

There are two different questions hiding inside "how long does alcohol stay in your system," and answering the wrong one is how people get caught out.

The first is about clearance: when is the alcohol actually gone from my blood? The second is about detection: when will a test stop finding evidence that I drank? Those answers differ by a factor of a hundred or more, because most modern alcohol tests do not look for alcohol at all. They look for what your liver left behind.

Both answers are ranges. Anyone quoting you a single number — seventeen hours, eighty hours, three days — is rounding away the part that matters.

How Fast Does Your Body Actually Clear Alcohol?

Almost all of the work happens in your liver, and it happens at a steady pace you cannot negotiate with. NIAAA puts it plainly: the body starts metabolizing alcohol within seconds, and proceeds at a steady rate, regardless of how much alcohol a person drinks or of attempts to sober up with caffeine or by other means.

The best evidence on what that rate is comes from forensic toxicology, where the number decides court cases. A 2010 review in Forensic Science International surveyed the literature and reported that the physiological range of ethanol elimination rates from blood is from 10 to 35 mg/100 mL/h. Within that range:

• 15 mg/100 mL per hour is described as a good average for moderate drinkers who have eaten.
• 10 to 15 mg/100 mL per hour for people who drank on an empty stomach.
• 19 mg/100 mL per hour is the more appropriate figure for apprehended drivers, many of whom are heavy drinkers.
• 25 to 35 mg/100 mL per hour in people with alcohol dependence during detoxification, because heavy drinking upregulates the enzymes involved.

Translated into everyday terms: a blood alcohol concentration of 0.15% takes roughly ten hours to reach zero at the average rate, and could take fifteen if you are on the slow end.

The "one drink an hour" rule is a floor, not a promise

The familiar rule of thumb says the body handles about one standard drink per hour. It is a reasonable starting point, but the arithmetic underneath it is worth seeing.

A US standard drink is any drink containing 14 grams, or about 0.6 fluid ounces, of "pure" ethanol — 12 oz of 5% beer, 5 oz of 12% wine, or a 1.5 oz shot of 80-proof spirits. Meanwhile the NHS, which built the UK unit system around the same physiology, defines one unit as 10ml or 8g of pure alcohol, which is around the amount of alcohol the average adult can process in an hour.

Eight grams an hour against a fourteen-gram drink. On those two official figures, a single US standard drink is closer to an hour and three quarters of clearance for an average adult than a tidy sixty minutes. The NHS adds the caveat that matters most: this will vary from person to person.

That gap is why people wake up still over the limit after a night they thought they had slept off. If you want to see the arithmetic run on your own numbers, the alcohol system calculator does it with the ranges intact rather than pretending to a single hour, and the BAC calculator covers the same math for the drinking window itself.

How Long Does Alcohol Stay in Your System by Test Type?

This is where the two questions separate. Breath, blood and saliva tests look for ethanol — the alcohol molecule — so they follow the clearance curve above. Urine, hair and specialist blood tests look for metabolites your liver produces, which linger long after the alcohol itself is gone.

The windows below come from a 2018 review of alcohol biomarkers in Deutsches Ärzteblatt International, plus a 1993 study in Clinical Chemistry on saliva.

Indirect markers are a separate category again. These are ordinary blood results that drift with heavy drinking and take weeks to settle: CDT normalizes about 2 to 3 weeks after stopping, GGT in 2 to 6 weeks, and MCV — red blood cell size — in 8 to 16 weeks. If you have stopped drinking and are waiting on liver numbers, that last column is the honest timeline. Our guide to what alcohol does to the liver covers what those markers actually mean.

What an EtG Test Really Tells You

EtG — ethyl glucuronide — is the test most people are asking about when they search this, usually because a job, a court order or a treatment program is involved. Two things about it are widely misreported.

The window is not a fixed 80 hours. The "80-hour test" is a marketing label. The peer-reviewed range is wider and depends entirely on how much you drank and what cutoff the lab uses: about 24 hours after small quantities, stretching to around 130 hours after heavy consumption. A single glass of wine and a weekend of heavy drinking are not the same test.

It can catch alcohol you did not drink. The same review documents positives from ethanol-containing mouthwash and from hand sanitizers, and notes that 2.5 litres of alcohol-free beer can produce a positive result for up to 20 hours. This is exactly why cutoffs exist and why a single EtG number should never be treated as proof on its own.

If a test result is what brought you here, the useful move is to ask which test, which cutoff, and what window the lab claims — not to look for a number online and hope.

How Long Does Alcohol Stay in Your System After a Heavy Night?

Take a night that ends at 1 a.m. with a blood alcohol concentration around 0.16% — roughly what a steady evening of drinking produces for many people.

At the average elimination rate of 15 mg/100 mL per hour, that is a little under eleven hours to zero: about midday. At the slower end of the published range it is closer to sixteen hours. Meanwhile the hangover has its own clock — NIAAA notes that hangover symptoms peak when the blood alcohol concentration in the body returns to about zero and can last 24 hours or longer. So the worst of how you feel arrives after the alcohol has gone, which is one reason people misjudge how long they were impaired. The same rebound drives hangxiety.

None of this is a moral scoreboard. A late night is a data point about pace and quantity, and the clearance math is the same for everyone regardless of how the evening went.

What Speeds Alcohol Clearance Up? Nothing

This is the section that saves the most trouble. NIAAA's hangover fact sheet addresses the folk remedies directly: certain actions, such as drinking coffee or taking a shower, can prevent or cure a hangover is listed as a myth, and the fact given underneath is that there is no cure other than time. The same page adds that there is no way to speed up the brain's recovery from alcohol use — drinking coffee, taking a shower, or having an alcoholic beverage the next morning will not cure a hangover.

Worth being precise about each one:

• Coffee does not change your elimination rate. It changes how awake you feel, which is worse than useless if you are deciding whether to drive.
• Cold showers do the same thing: a jolt of alertness on top of an unchanged blood alcohol concentration.
• Exercise and sweating clear a trivial fraction. The liver does essentially all of the work, at its own pace.
• Water helps with the dehydration side of a hangover. It does not accelerate metabolism.
• Food matters before drinking, not after. Eating slows absorption — NIAAA notes drinking on an empty stomach raises blood alcohol faster — but once the alcohol is in your blood, food changes nothing about how quickly it leaves.
• Sleep passes the time, which is the only thing that works. It does not add to the rate.

The one genuine lever is the one you pull before the first drink: how much, how fast, over how long. Spacing drinks with water — zebra striping — lowers the peak you have to clear later, and the alcohol units calculator shows how quickly a large glass of wine or a strong beer stops being one drink.

No Page Can Clear You to Drive

Including this one, and including our calculator.

Every estimate on this site, and every estimate anywhere else, is built on averages: an assumed elimination rate, an assumed body water fraction, an assumed absorption curve. Your real rate on a given morning sits somewhere in a range that spans more than threefold, and none of us can measure which end you are on. A tool that outputs "you are at 0.00%" is telling you what the model says, not what your blood says.

So the rule is simple and it is not negotiable: if you drank last night and you are not certain, do not drive. Use the drink driving limit tool to understand what the legal thresholds are and how long the math suggests they take to clear, then leave a wide margin on top of the answer. Impairment does not politely stop at the legal number, and the legal number is not a target.

What Moves the Numbers for You

Individual variation is not a rounding error here — it is most of the story. The published elimination range spans 10 to 35 mg/100 mL per hour because of factors including:

Liver size and body mass. NIAAA notes the rate varies widely among individuals depending on factors including liver size and body mass, as well as genetics.

Genetics. Variations in the ADH and ALDH genes change how fast each step of the breakdown runs. Some variants, common in people of East Asian descent, slow the second step and cause flushing.

Drinking history. Heavy regular drinking speeds elimination by upregulating the enzyme systems involved — the reason detoxifying patients clear at 25 to 35 mg/100 mL per hour. This is metabolic tolerance, and it is a marker of adaptation rather than a benefit.

Whether you ate. Fasted subjects sit at the slow end, 10 to 15 mg/100 mL per hour.

Sex and body composition. Alcohol distributes in body water, so the same drink produces a higher peak in a smaller person and in a body with a lower water fraction — which is why the same night looks different on two people who drank identically.

If you have started tracking, the first thing most people learn is how far their real numbers sit from the rule of thumb. That is the point of tracking: not a verdict, just a clearer picture of what your body is actually doing with what you give it.

References

1. National Institute on Alcohol Abuse and Alcoholism (NIAAA). "The Basics: Defining How Much Alcohol is Too Much." https://www.niaaa.nih.gov/health-professionals-communities/core-resource-on-alcohol/basics-defining-how-much-alcohol-too-much
2. NHS. "Alcohol units." https://www.nhs.uk/live-well/alcohol-advice/calculating-alcohol-units/
3. Jones AW. "Evidence-based survey of the elimination rates of ethanol from blood with applications in forensic casework." Forensic Science International. 2010;200(1-3):1-20. https://pubmed.ncbi.nlm.nih.gov/20304569/
4. Andresen-Streichert H, Müller A, Glahn A, Skopp G, Sterneck M. "Alcohol Biomarkers in Clinical and Forensic Contexts." Deutsches Ärzteblatt International. 2018;115(18):309-315. https://di.aerzteblatt.de/int/archive/article/197680
5. Jones AW. "Pharmacokinetics of ethanol in saliva: comparison with blood and breath alcohol profiles, subjective feelings of intoxication, and diminished performance." Clinical Chemistry. 1993;39(9):1837-1844. https://pubmed.ncbi.nlm.nih.gov/8375057/
6. National Institute on Alcohol Abuse and Alcoholism (NIAAA). "Hangovers." https://www.niaaa.nih.gov/publications/brochures-and-fact-sheets/hangovers

Frequently Asked Questions

How long does alcohol stay in your system for a urine test?

It depends on which urine test. A plain ethanol test follows the blood window and clears within hours. An EtG or EtS test looks for metabolites and runs far longer: detectable within an hour of drinking, about 24 hours after small amounts, and up to around 130 hours after heavy consumption. The lab's cutoff changes the answer as much as the drinking does.

Can you sober up faster with coffee, a cold shower or exercise?

No. NIAAA lists coffee and showers as myths and states there is no cure other than time. Metabolism proceeds at a steady rate regardless of caffeine or other attempts to sober up. What those things change is how alert you feel, which is genuinely dangerous if you are using that feeling to decide whether you are safe to drive.

How long after drinking can I drive?

No page, tool or calculator can answer that for you, because published elimination rates vary more than threefold between people. The honest guidance is to leave a wide margin, and if there is any doubt at all, do not drive. Our drink driving limit tool explains the legal thresholds, but a legal threshold is not a safety guarantee.

Why does an EtG test show alcohol days after I stopped drinking?

Because EtG is not alcohol. It is a metabolite your liver produces while processing ethanol, and it is cleared much more slowly than the ethanol itself. That is the point of the test — it is designed to see past the overnight window. It can also pick up incidental exposure from mouthwash, hand sanitizer, or large amounts of alcohol-free beer.

Does drinking a lot mean I clear alcohol faster?

Somewhat, and it is not good news. Heavy regular drinking upregulates the enzymes that break alcohol down, which is why people in detoxification clear at 25 to 35 mg/100 mL per hour against an average of 15. That faster rate is metabolic tolerance — a sign the body has adapted to a steady supply, not a sign it is handling alcohol well.

What to Read Next

• Hangxiety: Why You Feel Anxious the Morning After Drinking
• How Alcohol Tolerance Builds — and Why That's a Problem
• How Alcohol Damages the Liver: A Plain-Language Guide