Sleep & wake-up
Recovery sleep calculator
Enter how many hours of sleep you owe to see roughly how many nights of extra rest it takes to recover.
You cannot clear a big sleep debt in one lie-in. Adding about 1.5 extra hours a night lets you recover steadily without wrecking your schedule.
How sleep debt is repaid
Sleep debt is the gap between the sleep you need and the sleep you actually get. A late week or a few short nights leaves a running total, and the good news is that it can be paid back. The catch is that you cannot clear it all in a single marathon lie-in. Repaying it gradually, by adding around an hour and a half of extra sleep each night, is gentler on your body clock and easier to keep up.
| Sleep debt | Rough recovery |
|---|---|
| 3 hours | about 2 nights |
| 6 hours | about 4 nights |
| 9 hours | about 6 nights |
Recovering well
Go to bed a little earlier rather than sleeping far into the morning, which protects your wake time and your body clock. A short early-afternoon nap can help on the heaviest days. Keep your wake time steady even on weekends, since a consistent rhythm is what lets the debt shrink night after night. If you are chronically short on sleep, treat the fix as a steady habit rather than a one-off catch-up.
Frequently asked questions
Can I catch up on sleep in one night?
Not fully. A single long night helps, but a sizeable debt takes several nights of extra rest to clear. Spreading recovery out is more effective than one very long sleep.
Is it better to sleep in or go to bed earlier?
Going to bed earlier is usually better. It adds sleep while keeping your wake time steady, which protects your body clock. Sleeping far into the morning can make the next night harder.
Do naps help clear sleep debt?
Short naps can chip away at it and ease daytime tiredness, especially on heavy days. Keep them to about 20 minutes and early in the afternoon so they do not disturb your night's sleep.