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How Long Does Alcohol Stay in Your System? Why It Varies
The NHS puts one unit of alcohol, 10 ml or 8 g of pure alcohol, at "around the amount of alcohol the average adult can process in an hour", and adds that "this will vary from person to person".1 Six units, two pints of higher-strength lager, take the average adult about six hours; a bottle of wine is 10 units and about ten.1, 2 Nothing you eat, drink or do speeds that up; only time does.3 This page sits inside how to not be hungover.
How fast does the body clear alcohol?
The NHS Alcohol units page (last reviewed 27 August 2024) says: "One unit equals 10ml or 8g of pure alcohol, which is around the amount of alcohol the average adult can process in an hour. This means that within an hour there should be, in theory, little or no alcohol left in the blood of an adult, although this will vary from person to person."1 The table applies that line to the NHS unit figures and describes the average adult, in theory, as the NHS puts it. Clearance runs while you are still drinking, so the hours count from the first drink. How many units are in a drink has the full list.
| Drink (NHS unit figure) | Units | Time until little or none is left (average adult, in theory) |
|---|---|---|
| Single small shot of spirits (25 ml, 40% ABV) | 1 | About 1 hour |
| Standard glass of wine (175 ml, 12% ABV) | 2.1 | About 2 hours |
| Pint of higher-strength lager, beer or cider (5.2% ABV) | 3 | About 3 hours |
| Two pints of higher-strength lager, beer or cider | 6 | About 6 hours |
| Bottle of wine (750 ml, 13.5% ABV) | 10 | About 10 hours |
Why does it vary so much between people?
A forensic review of the elimination studies gives the spread: on an empty stomach, blood alcohol falls by 10 to 15 mg per 100 ml an hour; after food, 15 to 20; the whole physiological range is 10 to 35, and "in moderate drinkers 15 mg/100mL/h remains a good average value". The decline is "slightly steeper in women compared with men".4 So "one unit an hour" is an average, not your figure. Drinkaware lists what moves it: "your size, whether you are male or female, how much food you've eaten, the state of your liver, and your metabolism".3 The rate matters beyond the clock: a review of the metabolism studies concludes that "fast elimination of ethanol is associated with experiencing less severe hangovers".5
Does eating change how long alcohol stays in your system?
It changes the peak more than the clock. In 16 volunteers who drank the same dose fasting, after a snack and after a light meal, peak breath alcohol averaged 30.5 µg per 100 ml fasting and 21.4 after the meal, and the alcohol available for absorption after a meal fell "to only 66% in females and 71% in males".6 Elimination moves too: with alcohol given intravenously, so food could not affect absorption, a breakfast raised the elimination rate by 25% in a study of 20 people and by 45% in a second of eight, "regardless of composition", so no particular food has been shown to do more than any other.7 Neither study measured a hangover. The NHS advice: "Try to have something to eat, and drink a glass of water, before you have alcohol. Alternate alcoholic drinks with water or other non-alcoholic drinks."8 More in what to eat and drink before drinking alcohol.
Can you sober up faster?
No. Drinkaware: "There's nothing you can do to speed up the rate alcohol leaves your system. Having a cup of coffee or a cold shower won't do anything to get rid of the alcohol." And: "The only way to eliminate alcohol from the body is to let time pass."3 The same goes for peeing, sweating, water and food: alcohol is cleared "mainly by oxidative metabolism in the liver", at the hourly rates above, whatever you do in the meantime.4 Peeing a lot is water leaving, not alcohol; drinking water replaces fluid without moving the clock; nothing eaten after drinking has been shown to change the rate.3
"I woke up still drunk" is the arithmetic above: ten units at midnight are, in theory, still being cleared at 8am, and a slow clearer has longer to go. If someone cannot be woken or is breathing slowly or irregularly, the NHS says: "Call 999 if: you think someone has alcohol poisoning; you or someone else has had a seizure or fit; someone has lost consciousness; someone has stopped breathing." While you wait, do not give them coffee or caffeine, and do not put them in a cold shower or bath.9
What are the "rules" people talk about?
The "20 minute rule" is a pacing tip from mindful-drinking advice: wait 20 minutes after finishing one drink before starting the next. No trial has tested it, and a pause does not change the clearance rate; the NHS version is "drink more slowly" and "alternate your drinks with water or non-alcoholic drinks".10 The "1-2-3", "2-2-2" and "3-drink" rules are circulated drink counts with no evidence base, and no count avoids a hangover: a 2020 paper concluded that the field's 0.11% blood-alcohol threshold "should be abandoned", because "subjective intoxication, i.e., the level of severity of reported drunkenness, and not BAC, is the most important determinant of hangover severity", and hangovers follow when drinking "significantly exceeds their 'normal' drinking level".11 The "seven levels" or "seven stages" of drunk are not a medical scale.
The NHS defines binge drinking as "drinking more than 8 units of alcohol in a single session for men, or more than 6 units in a single session for women", which answers "is four drinks in three hours too much?" in units.10 Its weekly guidance: "men and women are advised not to drink more than 14 units a week on a regular basis", "spread your drinking over 3 or more days if you regularly drink as much as 14 units a week" and "try to have several drink-free days each week". "If you drink less than 14 units a week, this is considered low-risk drinking. It's called 'low risk' rather than 'safe' because there's no safe drinking level."10
Can alcohol still be in your system the next morning?
Yes. Drinkaware: "Even if you've been to sleep after drinking, there could still be high levels of alcohol in your system".3 Sleep is not a clearance method; the rate carries on through the night, so what is left at 7am is set by how much was drunk and when.4 Even at near-zero blood alcohol the day is not back to normal: a meta-analysis of 19 studies, 1,163 people tested at under 0.02% blood alcohol, found memory, sustained attention and psychomotor speed measurably worse during a hangover.12 Questions about driving are for the law and a breathalyser, not this page. Why some mornings are worse than the units predict is in why your hangovers feel so bad.
How does this connect to sleep and the next morning?
A review of every polysomnography study in healthy volunteers found that "at all dosages, alcohol causes a reduction in sleep onset latency, a more consolidated first half sleep and an increase in sleep disruption in the second half of sleep", with the first REM period delayed at every dose.13 That second-half disruption is why alcohol wakes you up at 3am; the next day is in what to eat and drink with a hangover.
Frequently asked questions
How long does alcohol stay in your urine or blood?
In blood, the NHS line applies: around a unit an hour for the average adult, varying from person to person.1 Detection in urine, breath or hair depends on the test and what it measures; this page does not give detection windows.
Does drinking water sober you up?
No. Water replaces fluid; it does not change the rate at which the liver clears alcohol.3
Does coffee sober you up?
No. "You might feel slightly different, but you won't have eliminated the alcohol in any way."3
Will two hours of sleep sober you up?
No. Clearance continues in sleep at the same rate it runs awake, so two hours removes, in theory, about two units' worth for the average adult; someone who drank ten units has eight to go.1, 3
Can you still be drunk seven hours after drinking?
Yes, if more than about seven units were drunk, on the NHS average; a slow clearer has longer still.1, 4
If you are worried about your drinking
"Drinkline is the national alcohol helpline. If you're worried about your own or someone else's drinking, you can call this free helpline in complete confidence. Call 0300 123 1110 (weekdays 9am to 8pm, weekends 11am to 4pm)." "A good place to start is with a GP."14 In Scotland, NHS inform lists Drinkline Scotland on 0800 7314 314.15 "If you stop drinking or cut down, you may get withdrawal symptoms. This is a sign your body is dependent on alcohol." "It can be very dangerous to stop drinking suddenly if you're dependent on alcohol. If you get withdrawal symptoms, get medical help before you try to stop drinking."16 "Call 999 if: you think someone has alcohol poisoning; you or someone else has had a seizure or fit; someone has lost consciousness; someone has stopped breathing."9
Sources
- NHS. Alcohol units (reviewed 27 August 2024). nhs.uk/live-well/alcohol-advice/calculating-alcohol-units
- Drinkaware. What is an alcohol unit? (last reviewed 19 July 2026). drinkaware.co.uk
- Drinkaware. Alcohol left in the body after sleep (drink-driving advice page, last reviewed 23 December 2024). drinkaware.co.uk
- Jones AW. Evidence-based survey of the elimination rates of ethanol from blood with applications in forensic casework. Forensic Sci Int 2010. PubMed 20304569
- Mackus M et al. The role of alcohol metabolism in the pathology of alcohol hangover. J Clin Med 2020. PubMed 33113870
- Sadler DW, Fox J. Intra-individual and inter-individual variation in breath alcohol pharmacokinetics: the effect of food on absorption. Sci Justice 2011. PubMed 21334574
- Ramchandani VA, Kwo PY, Li TK. Effect of food and food composition on alcohol elimination rates in healthy men and women. J Clin Pharmacol 2001. PubMed 11762562
- NHS. Tips on cutting down on alcohol (reviewed 9 April 2026). nhs.uk/live-well/alcohol-advice/tips-on-cutting-down-alcohol
- NHS. Alcohol poisoning (reviewed 4 June 2026). nhs.uk/conditions/alcohol-poisoning
- NHS. The risks of drinking too much (reviewed 10 September 2026). nhs.uk/live-well/alcohol-advice/the-risks-of-drinking-too-much
- Verster JC et al. Sensitivity to experiencing alcohol hangovers: reconsideration of the 0.11% blood alcohol concentration (BAC) threshold for having a hangover. J Clin Med 2020. PubMed 31936502
- Gunn C et al. A systematic review of the next-day effects of heavy alcohol consumption on cognitive performance. Addiction 2018. PubMed 30144191
- Ebrahim IO et al. Alcohol and sleep I: effects on normal sleep. Alcohol Clin Exp Res 2013. PubMed 23347102
- NHS. Alcohol support (reviewed 17 August 2026). nhs.uk/live-well/alcohol-advice/alcohol-support
- NHS inform. Alcohol support (updated 7 October 2026). nhsinform.scot/healthy-living/alcohol/alcohol-support
- NHS. Alcohol-use disorder (reviewed 24 April 2026). nhs.uk/conditions/alcohol-use-disorder
