Sleep Debt Calculator
Enter how many hours you slept each night for the last week or two. See how much sleep you owe compared with what your body needs, and a realistic plan to pay it back.
Hours slept each night
How to calculate your sleep debt
- Pick your age group to use the recommended sleep need, or set your own.
- Enter the hours you actually slept each night, not the time in bed. Use a sleep tracker or your best estimate.
- Read your total debt and nightly average. The plan shows how many nights of a little extra sleep it takes to recover.
What is sleep debt?
Sleep debt is the difference between the sleep your body needs and the sleep you actually get, added up over several nights. Sleeping six hours a night when you need eight builds two hours of debt a night, or 14 hours over a week. Even modest debt affects concentration, mood, reaction time and appetite, and people often underestimate how impaired they are because they get used to feeling tired.
How much sleep do you need?
| Age | Recommended per night |
|---|---|
| Teens 14–17 | 8–10 hours |
| Adults 18–64 | 7–9 hours |
| Adults 65+ | 7–8 hours |
These ranges come from the US National Sleep Foundation and the American Academy of Sleep Medicine. Your own need is the amount that leaves you alert all day without caffeine; one way to find it is to sleep without an alarm during a vacation after the first few days.
Paying it back
Short-term debt from the last week or two can be repaid. Adding 30 to 60 minutes a night, through an earlier bedtime rather than a later alarm, is the gentlest way. A long weekend lie-in helps a little, but sleeping in by several hours shifts your body clock and makes Sunday night and Monday morning harder (“social jet lag”). Long-term chronic shortage cannot be fully undone in a few nights, so a steady routine matters more than catching up.
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Frequently asked questions
Can you really catch up on lost sleep?
Partly. Recent debt can be recovered with extra sleep over several nights, and alertness improves. Years of short sleep cannot simply be made up with a few long nights.
Do naps count?
Yes. Add nap time to that day’s total. A 20-minute nap early in the afternoon refreshes without making it harder to sleep at night.
Should I count time in bed or time asleep?
Time actually asleep. Most people take 10–20 minutes to fall asleep and wake briefly during the night.
When should I see a doctor?
If you sleep enough hours but still feel exhausted, snore loudly, stop breathing during sleep, or struggle with insomnia most nights, talk to a doctor. These can be signs of a treatable sleep disorder.
Is anything sent to a server?
No. Everything is calculated in your browser, and nothing you enter leaves your device.