How is your week of sleep adding up?
Add the past seven nights and gently compare them with the amount of sleep that feels right for you.
What “deficit” means here
For each night below your target, we add the difference. Nights above the target are reported as surplus but do not automatically erase prior shortfalls.
This makes the result useful as a behavior prompt while avoiding a claim that biological recovery works like a bank balance.
Formula
Weekly deficit = sum of max(target − hours slept, 0) for seven nights.
A recurring large shortfall matters more than a single imperfect night. Focus on a sustainable schedule rather than chasing a perfect zero.
Common questions
Is sleep debt a precise medical number?
No. This tool calculates a simple difference from a personal target. Actual recovery from sleep loss is more complex and varies by person, timing, and duration of restriction.
Can I repay five lost hours in one night?
A longer night may help, but sleep recovery is not a precise hour-for-hour bank transaction. That is why we show longer-night surplus separately instead of automatically canceling every deficit.
What sleep target should I use?
Most healthy adults should regularly get at least seven hours. Choose a realistic personal target based on how you function and any guidance from your healthcare professional.
Why use seven nights?
One week captures both workdays and weekends and is easy to remember. It is a planning snapshot, not a long-term assessment.