😴Sleep Debt Calculator

About this tool

Choose your age group (or set your own sleep need) and enter the hours you actually slept on each of the last seven nights. The tool totals your sleep debt, shows your average and how far short you are each night, and suggests a recovery plan with 30 minutes to an hour of extra sleep a night. Nothing is stored.

What sleep debt is and how to recover

Sleep debt is the gap between the sleep your body needs and the sleep you get, added up over days. Guidance from the US National Sleep Foundation and the American Academy of Sleep Medicine is 7–9 hours for adults, 8–10 for teenagers and 7–8 for over-65s, though individual needs vary. Even an hour short a night adds up to a full night's sleep lost each week. Studies show this kind of build-up affects reaction time, mood, memory and appetite, often without people noticing how impaired they are. In the example, a week averaging 7 hours against an 8-hour need is a 7-hour debt, which an extra hour a night clears in about seven nights. The best way to recover is gradual: go to bed a little earlier rather than sleeping in late, which shifts your body clock and makes Monday mornings harder. Keep a regular wake time, get daylight in the morning, and cut caffeine after early afternoon. Weekend catch-up sleep helps a little but doesn't fully reverse a week of short nights. Honest limits: count actual sleep, not time in bed, and see a doctor if you're exhausted despite enough sleep, snore heavily or have pauses in breathing. Not medical advice. The sleep calculator and the caffeine calculator are related, and Sleep cycles, and waking up less awful explains sleep cycles.

Frequently asked questions