How to use it
- Set the nightly sleep you aim for.
- Enter roughly how many hours you slept each of the last seven nights.
- Review your nightly and weekly shortfall.
Understanding your results
Shortfall is the sum of hours below your goal on each night. Nights where you slept more than your goal don't cancel out shorter nights in this estimate.
Recovering gently
Sleep debt is an approximation and can't always be repaid hour-for-hour. Rather than one very long lie-in, many people do better adding 30–60 minutes per night over several days, keeping a steady wake time, and protecting a regular bedtime.