Sleep Debt Calculator
Enter how many hours you slept each night. Sleep debt is the gap between what you need and what you got.
What sleep debt means
Sleep debt is the gap between the sleep you need and the sleep you actually get, added up over the week. If you need 8 hours and sleep 6.5 each weeknight, that's 7.5 hours of debt by Friday.
Most adults need at least 7 hours a night. You can't fully repay a big debt in one long lie-in; going to bed 30–60 minutes earlier for several nights works better and keeps your body clock steady. Ongoing tiredness despite enough sleep is worth discussing with a doctor.
More time tools
Questions
How much sleep do adults need?
The CDC recommends 7 or more hours a night for adults aged 18 to 60.
Can you catch up on lost sleep?
Partly. Adding an hour or two a night over several days helps; one very long lie-in doesn't fully reset the week.