Results are estimates for healthy adults unless stated, and are not medical advice. Your doctor or a registered dietitian can give advice for your situation.
Sleep debt is the gap between the sleep your body needs and the sleep you actually get. A few short nights add up, and the effects (tiredness, poor focus, low mood, more cravings) build up with them. This calculator adds up your last seven nights and gives you a simple catch-up plan.
How to use the sleep debt calculator
- Choose how much sleep you need. Most adults need 7–9 hours; teenagers need 8–10.
- Enter roughly how many hours you slept on each of the last seven nights.
- Press Calculate to see your total debt, your average and how to recover.
How sleep debt is calculated
The calculator multiplies your nightly need by seven, then subtracts the hours you actually slept. For example, if you need 8 hours (56 hours a week) but slept 6 hours a night on weeknights and 8 hours at the weekend, you slept 46 hours and your sleep debt is 10 hours.
How to pay back sleep debt
- Go to bed earlier: adding about an hour a night is easier on your body clock than sleeping in until midday.
- Keep your wake-up time steady: big weekend lie-ins shift your body clock and make Monday harder.
- Use short naps: a 20-minute nap in the early afternoon can take the edge off.
- Fix the cause: late screens, caffeine and irregular schedules are common reasons for short sleep.
Frequently asked questions
Can you fully catch up on lost sleep?
You can recover from a few short nights within days. Long-term sleep loss over months is harder to undo, which is why a regular sleep schedule matters more than weekend catch-up.
How do I know how much sleep I need?
On a holiday with no alarm, note how long you sleep after the first few days. That is close to your natural need. Most adults land between 7 and 9 hours.
When should I see a doctor?
If you feel exhausted even after enough sleep, snore loudly, stop breathing during sleep, or struggle to sleep most nights for more than a few weeks, talk to a doctor.
Sources
- American Academy of Sleep Medicine and Sleep Research Society – recommended sleep for adults
- Centers for Disease Control and Prevention (CDC) – sleep and health