Sleep debt calculator
Short answer: Enter how long you slept each night this past week and your sleep need. The calculator adds up the shortfall, shows your sleep debt, and suggests a bedtime that repays about a quarter of it tonight, never more than an hour earlier. It runs entirely in your browser.
How it's calculated
For each night, the shortfall is your sleep need minus the hours you slept. Nights above your need reduce the total, which never goes below zero. Tonight's bedtime moves earlier by 25% of the debt, capped at 60 minutes. That's the same rule Pulse Coach uses with 14 nights of Apple Watch data.
Read more: what is sleep debt?
Questions people also ask
How much sleep do I need?
Most adults need at least 7 hours; many feel best with 7.5–8.5. Use the amount you sleep on holidays, waking without an alarm, as a guide.
Why cap the bedtime change at one hour?
Moving bedtime by more than about an hour at once usually means lying awake. Small, consistent shifts repay debt more reliably.
Sources
Not medical advice. This article is general information about wellness metrics. It is not a diagnosis or a substitute for professional care. If a reading worries you, or you feel unwell, talk to a doctor.