Sleep Debt Calculator

Weekly sleep debt

The American Academy of Sleep Medicine puts the adult target at 7–9 hours per night. Sleep debt is just what builds up when you keep falling short of that ideal night after night. The calculator runs debt = Σ(ideal − slept) over the seven nights and skips any night where you actually slept extra. Example: lose 2h a day for 5 weekdays and you reach Friday with 10 hours of debt. A bit of sleep banking on the weekend, say one or two 10-hour nights, claws some of it back. Chronic insomnia is a different story, though: the debt it piles up only partly reverses, and the cognitive, immune, and metabolic costs tend to linger.

Applications

Think shift workers like nurses, drivers, and factory crews, new parents getting through that first year, students slogging through exam season, and anyone keeping an eye on burnout. Research in Sleep and the European Heart Journal ties a chronic deficit above 1h/night to higher cardiovascular mortality, obesity, type 2 diabetes, and more crashes on the road.

FAQ

Can I fully recover weekend debt? Sleeping in takes the edge off how drowsy you feel, but it won't reset your metabolic or attention markers all the way. A consistent schedule does more for you than a weekend binge.

What about surplus nights? The calculator only tallies the deficits. You can't really "save up credit" for the nights ahead beyond roughly 1–2 nights of catch-up.

And naps? A 20–30 minute nap dials down the acute drowsiness, but it can't stand in for the slow-wave sleep you lost.

When to seek help? If the debt sits above 10h/week and you're feeling it during the day, it's worth getting checked for insomnia, apnea, or a circadian rhythm disorder.