When will tonight's drinks clear?
A drink stays in you a lot longer than it feels. Put in your drinks and your bedtime, then drag the last one along the evening and watch the clear time slide across your bedtime.
Bed at 11:00pm
Mostly cleared by 2:50am
That's about 3.8 hours of your sleep with alcohol in your blood (3.1 to 4.9 if your liver runs faster or slower).
18.9 g, 1.35 US drinksoz%- 18.9 g, 1.35 US drinksoz%
The same drinks two hours earlier clear by 12:50am, about 1.8 hours of sleep with alcohol.
REM: More REM lost. Your evening is 0.56 g of alcohol per kg of body weight.
In 20,968 WHOOP members, a night with one drink more than their usual, against one less, came with a sleeping heart rate 2.4 to 2.8 beats higher and HRV 3.3 to 3.8 ms lower. Finishing an hour earlier than usual, against an hour later, came with a slightly lower heart rate that night. WHOOP paid for the study. The HRV side, on hrv.guide
With Gyroscope One, snap or tap each drink and see what it did to your resting heart rate and sleep. How it works
An average for your body. It doesn't know your medicines, your liver, a GLP-1 drug or how big your pour really was, and it never tells you whether you can drive. The absorption times are ours: 30 minutes on an empty stomach, 2 hours with a meal. For adults of legal drinking age, 21 in the US. If you're pregnant or trying, the CDC says there's no known safe amount of alcohol.
The worked evenings
A 150 lb woman, 6 oz glasses of 13.5% red wine, with dinner, in bed at 11pm. Each glass is 18.9 g of alcohol, 1.35 US drinks.
| Evening | Mostly cleared | Faster or slower liver | Hours of sleep with alcohol |
|---|---|---|---|
| Two glasses, finished at 8pm and 9pm | 2:50am | 2:05am to 3:55am | 3.8 |
| The same two at 6pm and 7pm | 12:50am | 12:05am to 1:55am | 1.8 |
| One glass at 8pm | 11:40pm | 11:20pm to 12:15am | 0.7 |
How the clock works
Grams first: fluid ounces x 29.57 x ABV x 0.789 gives the grams of alcohol in a pour, and a US standard drink is 14 g. The alcohol spreads through the water in your body, so the same drink gives a higher level in a smaller body, and in a female body, which holds less water pound for pound. We use Widmark's factors, 0.55 for a female body and 0.68 for a male one. Published values run from about 0.53 to 0.80 by sex and build.
Each drink comes into the blood over a window that starts when you finish it: 30 minutes on an empty stomach, 2 hours with a meal, 1 hour if you're not sure. Those windows are ours. In a lab study, the same dose after breakfast peaked about a third lower and cleared about 2 hours sooner than on an empty stomach. Our windows understate that, which is the safe direction.
Then the liver clears it. Once a drink or two is in, its enzyme is busy and the level falls by a fixed amount an hour: 10 to 15 mg per 100 mL on an empty stomach, 15 to 20 after eating, 15 a good average. It slows near the end. Mostly cleared means under 5 mg per 100 mL, and the band is the same evening on a faster and a slower liver.
What it does to your night
Across 27 studies, even a low dose, up to about 0.5 g of alcohol per kg of body weight, cut REM sleep, and more cut more. Falling asleep faster only showed up at about 0.85 g per kg. At every dose, the first half of the night ran deeper and the second half more broken.
The two halves of a drinking night
A dry night
After two glasses of wine at 8pm and 9pm, mostly cleared about 2:50am
In 20,968 WHOOP members, a night with one drink more than their usual, against one less, came with a sleeping heart rate 2.4 to 2.8 beats higher and HRV 3.3 to 3.8 ms lower. Finishing an hour earlier than usual, against an hour later, came with a slightly lower heart rate that night. WHOOP paid for the study.
Where the clock stops
An average for your body. It doesn't know your medicines, your liver, a GLP-1 drug or how big your pour really was, and it never tells you whether you can drive. Real clearing runs from 10 to 35 mg per 100 mL an hour, and your level can keep rising after your last drink. Check it against your own nights.
11 sources
- National Institute on Alcohol Abuse and Alcoholism, What Is A Standard Drink? Updated December 2025niaaa.nih.gov
- National Institute on Alcohol Abuse and Alcoholism, Drinking Levels and Patterns, updated January 2026niaaa.nih.gov
- US Centers for Disease Control and Prevention, About Alcohol Use During Pregnancy, reviewed August 14, 2026cdc.gov
- MedlinePlus, Calories in alcoholmedlineplus.gov
- Jones AW, Evidence-based survey of the elimination rates of ethanol from blood with applications in forensic casework, Forensic Science International, 2010pubmed.ncbi.nlm.nih.gov
- Searle J, Alcohol calculations and their uncertainty, Medicine, Science and the Law, 2015pmc.ncbi.nlm.nih.gov
- Jones AW, Jönsson KA, Food-induced lowering of blood-ethanol profiles and increased rate of elimination immediately after a meal, Journal of Forensic Sciences, 1994pubmed.ncbi.nlm.nih.gov
- Gardiner C and others, The effect of alcohol on subsequent sleep in healthy adults: a systematic review and meta-analysis, Sleep Medicine Reviews, 2025pubmed.ncbi.nlm.nih.gov
- Ebrahim IO, Shapiro CM, Williams AJ, Fenwick PB, Alcohol and sleep I: effects on normal sleep, Alcoholism: Clinical and Experimental Research, 2013pubmed.ncbi.nlm.nih.gov
- Chan JKM and others, The acute effects of alcohol on sleep architecture in late adolescence, Alcoholism: Clinical and Experimental Research, 2013pubmed.ncbi.nlm.nih.gov
- Grosicki GJ and others, Real-world effects of alcohol on heart rate, sleep, and physical activity by age and sex, PLOS Digital Health, 2026 (funded by WHOOP)pubmed.ncbi.nlm.nih.gov
