Sleep Debt Calculator: how far behind are you?
Enter how long you slept on each of the last seven nights and see your sleep debt and a gentle catch-up plan.
Hours slept each night (leave blank to skip):
How it is calculated
For each night below your target we add the shortfall. Nights above your target reduce the total by half of the surplus. The catch-up figure is only an example scenario that assumes one extra hour of sleep per night; real recovery varies from person to person.
Ways to catch up
- Move bedtime earlier by 30 to 60 minutes rather than sleeping in.
- Keep wake-up time steady, even on weekends, within about an hour.
- Use a short early-afternoon nap if needed.
Want everyday habits to try alongside this estimate? Read our practical guide to better sleep.
Frequently asked questions
What is sleep debt?
The gap between the sleep you need and the sleep you actually get, added up over several nights.
Can I pay it back on the weekend?
Partly. Extra sleep helps, but research suggests a single weekend rarely erases a week of short nights. Gradual recovery of about an hour extra per night is gentler and easier to sustain.
How much sleep do I need?
Most adults need 7 to 9 hours. Use the Bedtime Calculator to see recommended ranges by age.
Why does extra sleep count only half?
It is a simplification we chose, not a published physiological formula. Research suggests extra sleep on one night may not fully offset earlier short nights, so we credit surplus at 50% to avoid overstating recovery.
More sleep tools
Sleep Calculator
Find the bedtime or wake-up time that lines up with your sleep cycles.
Nap Calculator
Pick a nap length and see when to set the alarm.
Caffeine Calculator
How much caffeine is still in you at bedtime, and your last-call time.
Bedtime Calculator
Age-based bedtime range for a given wake-up time.