The Nightcap Curve
Is your nightcap still with you at 2 a.m.? Log tonight's drinks and your bedtime to see how far into your sleep the alcohol is still clearing — through the stretch of the night it disrupts most — and the honest range your body might really be in.
14 g alcohol
5 oz wine · 12 oz beer · 1.5 oz spirits (US; CA uses 13.45 g)
~1 drink / 1.5–2 h
≈0.015%/h — and it genuinely varies person to person
Back half of the night
REM suppression while alcohol is still clearing
Each drink becomes a standard-drink amount of pure alcohol, absorbs over about 45 minutes, and then clears at a steady rate — roughly one standard drink every hour and a half to two hours. Unlike caffeine, alcohol leaves at a fixed pace, so two drinks take about twice as long as one. Because clearance truly varies — body size, sex, food, genetics — we always draw a range, not a single confident line.
Alcohol can make falling asleep feel easier — then collect the debt later. Sleep research links the hours when alcohol is still clearing, concentrated in the second half of the night, with suppressed REM and more fragmented sleep. That's the stretch this tool shades: see how far tonight's drinks reach into it, and how much an earlier last call pulls them back.
This tool is educational, not medical advice — and never a guide to whether it's safe to drive. Standard-drink and guidance figures are quoted from the US Dietary Guidelines and CCSA 2023; clearance modeling uses published pharmacokinetics with individual variation shown as a range. Nothing you enter is stored — inputs live only in this page's URL.