Sleep debt tracker
Sleep debt calculator
Sleep debt accumulates quietly. The dangerous part is that you stop noticing the impairment well before the impairment stops. Enter your last 7 nights, set your personal target, and see where you actually stand.
Hours slept (last 7 nights)
Nightly sleep vs. target
Cumulative deficit is high enough to measurably degrade reaction time, mood, and decision-making — even if you feel fine. Plan a recovery week.
How to pay it back
- What time should I go to bed tonight?Debt clears over a week of consistent, slightly longer nights — not one 12-hour weekend lie-in.
- Can a nap clear sleep debt?Partly. Naps restore alertness within the day but do not repay the accumulated deficit.
- Am I an early bird or a night owl?Chronic debt is often social jet lag — an owl's biology fighting a lark's alarm clock, five days a week.
- How much sleep do I actually need?The target this debt is measured against changes with age. Check yours before trusting the number.
How debt is calculated
For each night where you slept less than your target, the difference adds to your debt. Nights above target don't bank credit — research (Van Dongen et al., Sleep 2003) shows surplus sleep doesn't store the way deficit does. The "days to recover" figure assumes you can add up to 2 extra hours per night before the body resists; chronic large debts pay down slower than that in practice.
The harshest finding in the literature: after two weeks of 6 hours per night, participants in the Van Dongen study performed as poorly as people fully sleep-deprived for two consecutive nights — but they consistently rated themselves as only "a little tired." Don't trust your subjective sense of recovery. Trust the math.
Sources: Van Dongen et al., Sleep 2003· CDC sleep recommendations· Depner et al., Curr Biol 2019 (weekend recovery limits)