Alcohol the morning after
Yes, alcohol can still be in your blood the morning after drinking. The body removes it at a roughly steady rate that sleep does not speed up, so a late or heavy night can leave a measurable blood alcohol level well into the next day. Log last night in the calculator to see an estimate with a range.
Why alcohol is still there in the morning
Blood alcohol falls by roughly 0.015 g/dL per hour in an average moderate drinker, and forensic guidance uses a range of 0.010 to 0.025 g/dL per hour. A level of 0.15 % at 1 am therefore takes about 10 hours to clear at the average rate and as long as 15 hours at the slow end. Going to bed does not change that arithmetic.
Sources: Jones AW, Evidence-based survey of the elimination rates of ethanol from blood with applications in forensic casework; AAFS Standards Board, Best Practice Recommendation for Performing Alcohol Calculations in Forensic Toxicology.
Road-safety authorities say the same in plain words: you may be over the legal limit many hours after your last drink, even if you have slept all night, and only time reduces the alcohol in your body.
Sources: nidirect, Drink driving; Queensland Government, Drink responsibly.
How to log last night
- Open the blood alcohol calculator and enter your weight and the sex option you chose.
- Choose One at a time and add each drink. Under “When?” pick Choose time, then Yesterday. A drink that ran past midnight is handled for you: enter 23:30 to 00:30 and the finish is placed on the next day.
- If you had several of the same drink, set the count and the period, for example three beers between 8 pm and 11 pm. They are spread evenly and each one can be edited afterwards.
- If you are not sure when a drink was, tick “I don’t remember exactly” and give the period it fell in. The estimate then covers the drink being early or late in that period.
Prefer a quick answer? Several at once takes a count of drinks plus Last night or the times you started and finished, and assumes they were spread evenly in between.
How to read the morning estimate
- Look at the range, not only the centre. If the upper end is still well above zero, a slow eliminator with your inputs would still have alcohol in their blood.
- Underestimating last night is easy. Home pours, strong beers and forgotten drinks all push the real level above the estimate. NIAAA notes that drinks often contain more alcohol than people think.
- “Below 0.02 %” is not zero. The model is unreliable at low levels and real elimination slows at the very end.
Sources: National Institute on Alcohol Abuse and Alcoholism, The Basics: Defining How Much Alcohol is Too Much; AAFS Standards Board, Best Practice Recommendation for Performing Alcohol Calculations in Forensic Toxicology.
Near zero does not mean recovered
Hangover symptoms peak when blood alcohol returns to about zero and can last 24 hours or longer. During a hangover, attention, decision-making and muscle coordination can all be impaired, and the ability to drive or operate machinery can be affected.
Sources: National Institute on Alcohol Abuse and Alcoholism, Hangovers.
Research points the same way. A systematic review found that sustained attention and driving ability were impaired during hangover, and a driving-simulator study of 18 to 25-year-olds found impairment comparable to alcohol-impaired driving even when breath alcohol was zero.
Sources: Gunn C, A systematic review of the next-day effects of heavy alcohol consumption on cognitive performance; Alford C, The Impact of Alcohol Hangover on Simulated Driving Performance during a 'Commute to Work' — Zero and Residual Alcohol Effects Compared.
Do not use an estimate to decide whether to drive the next morning. If you drank heavily last night, arrange not to drive. A calculator cannot measure your blood alcohol, and it knows nothing about tiredness or a hangover.
Sources: UK Department for Transport, THINK! Drink driving.
What does not speed it up
| Remedy | Effect on blood alcohol | What it may do |
|---|---|---|
| Sleep | None beyond the time that passes | Reduces tiredness |
| Coffee | None | Helps with drowsiness, not with judgement or coordination |
| Cold shower | None | Makes you feel more awake |
| Breakfast or water | None on alcohol already absorbed | May ease some hangover symptoms |
| Another drink | Raises it | Can prolong the hangover |
Sources: National Institute on Alcohol Abuse and Alcoholism, Hangovers; National Institute on Alcohol Abuse and Alcoholism, The Truth About Holiday Spirits; nidirect, Drink driving.
If someone is hard to wake
Blood alcohol can keep rising after a person stops drinking or passes out. Someone who cannot be woken, is breathing slowly or irregularly, or is vomiting while drowsy needs emergency help, whatever time it is and whatever any estimate says. See alcohol poisoning: get help.
Sources: National Institute on Alcohol Abuse and Alcoholism, Understanding the Dangers of Alcohol Overdose.
Sources
- National Institute on Alcohol Abuse and Alcoholism (NIAAA). Hangovers. niaaa.nih.gov (checked 6 November 2026)Hangover symptoms peak when blood alcohol returns to about zero and can last 24 hours or longer; attention, decision-making and coordination can be impaired; no cure other than time.
- National Institute on Alcohol Abuse and Alcoholism (NIAAA). The Truth About Holiday Spirits. niaaa.nih.gov (checked 6 November 2026)Alcohol keeps entering the bloodstream after the last drink; coffee does not sober you up; food slows absorption.
- National Institute on Alcohol Abuse and Alcoholism (NIAAA). Understanding the Dangers of Alcohol Overdose. niaaa.nih.gov (checked 6 November 2026)Critical signs of alcohol overdose; do not wait for all symptoms; blood alcohol can keep rising after drinking stops; what to do while waiting for help.
- National Institute on Alcohol Abuse and Alcoholism (NIAAA). The Basics: Defining How Much Alcohol is Too Much. niaaa.nih.gov (checked 6 November 2026)How alcohol is absorbed, distributed and metabolised; effect of an empty stomach; body-water difference between women and men; drinks often contain more alcohol than people think.
- nidirect (Northern Ireland Executive). Drink driving. nidirect.gov.uk (checked 6 November 2026)You may be over the legal limit many hours after your last drink, even after a night's sleep; sleep, breakfast, coffee or a cold shower will not sober you up.
- Queensland Government. Drink responsibly. qld.gov.au (checked 6 November 2026)Only time reduces blood or breath alcohol concentration.
- UK Department for Transport. THINK! Drink driving. think.gov.uk (checked 6 November 2026)You cannot reliably calculate how much you can drink and stay under a legal limit; feeling fine does not mean your driving is unaffected.
- 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. pubmed.ncbi.nlm.nih.gov (checked 6 November 2026, abstract only)15 mg/100 mL per hour as a good average elimination rate for moderate drinkers; physiological range 10–35; zero-order kinetics adequate above 20 mg/100 mL.
- AAFS Standards Board. Best Practice Recommendation for Performing Alcohol Calculations in Forensic Toxicology. ANSI/ASB Best Practice Recommendation 122, First Edition, 2024. aafs.org (checked 6 November 2026)Formula (dose ÷ (Vd × body mass)); volume-of-distribution ranges by sex; elimination range 0.010–0.025 g/dL per hour; ranges instead of single values; linear elimination unreliable below 0.020 g/dL; up to 2 hours to finish absorbing; ethanol density 0.789 g/mL.
- Alford C, Broom C, Carver H, et al.. The Impact of Alcohol Hangover on Simulated Driving Performance during a 'Commute to Work' — Zero and Residual Alcohol Effects Compared. Journal of Clinical Medicine 2020;9(5):1435. pmc.ncbi.nlm.nih.gov (checked 6 November 2026)Simulated driving was impaired during a hangover even when breath alcohol was zero.
- Gunn C, Mackus M, Griffin C, Munafò MR, Adams S. A systematic review of the next-day effects of heavy alcohol consumption on cognitive performance. Addiction 2018;113(12):2182–2193. pmc.ncbi.nlm.nih.gov (checked 6 November 2026)Sustained attention and driving ability were impaired during hangover.