Habits
Sleep Debt Calculator
Sleep debt is the gap between the sleep you need and the sleep you actually get. Short weeknights followed by long weekend lie-ins are a common pattern. Enter your nightly need, your typical weeknight sleep and your weekend sleep to see the weekly gap and what it averages out to per night.
How it works
Weekly need = nightly need x 7. Sleep obtained = weeknight hours x 5 + weekend hours x 2. Sleep debt = need minus sleep obtained, never below zero. The per night figure divides the weekly debt by 7.
Example
Need 8 h, weeknights 6.5 h, weekends 8.5 h. Need 56 h; got 6.5 x 5 + 8.5 x 2 = 49.5 h. Debt = 6.5 h a week, about 56 minutes a night.
Assumptions and limits
- Use time actually asleep, not time in bed.
- The summary bands are simple per night averages chosen for this tool, not clinical categories.
- Research suggests weekend catch-up sleep does not fully reverse the effects of repeated short sleep, so a lower debt is better than a later recovery.
- If you get enough hours and still feel very sleepy, sleep quality may be the problem, for example from sleep apnea.
Frequently asked questions
Can I pay back sleep debt on the weekend?
Partly. Extra sleep helps you feel more alert, but studies of recovery sleep suggest it does not fully undo the effects of a week of short nights on attention and metabolism. Getting enough sleep most nights is the better fix.
How do I know my sleep need?
For adults the recommendation is at least 7 hours. A practical test is how much you sleep on a vacation after the first few days, waking without an alarm and feeling alert during the day.
Is sleep debt dangerous?
Ongoing insufficient sleep is linked by NHLBI and others to higher risk of accidents, heart disease, high blood pressure, obesity, diabetes and depression, and drowsy driving is a serious hazard.
Sources
Tools and screening scores are general information. They cannot diagnose or rule out a sleep disorder. Read our medical disclaimer.