Comprehensive Calculator Guide
Sleep debt is the total of the hours you slept below your need over several nights. Needing 8 hours and getting 6.5 each night adds up to 10.5 hours in a week, more than a full night. Enter your need, average sleep and number of nights to see yours.
How much you need, and catching up
The American Academy of Sleep Medicine and the Sleep Research Society recommend 7 or more hours a night for adults; needs vary, and children and teenagers need more.
Weekend lie-ins ease some sleepiness but do not undo it all and can unsettle the next week. Adding 30–60 minutes a night for several days works better. Heavy daytime sleepiness despite enough sleep, or loud snoring, is worth a doctor's visit.
How to Use
- 01Enter the sleep you need per night.
- 02Enter your average actual sleep.
- 03Enter the number of nights.
Formula Used
Sleep debt = (need − average sleep) × nightsPractical Examples
Example 1
Need 8, sleep 6.5, 7 nights: 10.5 hours.
Example 2
Need 7.5, sleep 6, 5 nights: 7.5 hours.
Important Tips
- Keep the same wake-up time every day.
Common Mistakes to Avoid
- Counting time in bed as sleep.
Frequently Asked Questions
- What is sleep debt?
- The hours of sleep you missed against your need.
- How much sleep do adults need?
- 7 hours or more, regularly.
- Can I catch up at the weekend?
- Only partly; add sleep gradually over several nights.