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Sleep Debt Calculator

How far behind on sleep you are this week, and how long it takes to catch up.

Your details

Units

From your profile. Changes here update it everywhere.

Sets your usual sleep need: 8 h, or 7.5 h from 65.

Average sleep per night, last week

If you know it, e.g. how long you sleep on holiday without an alarm.

For general information only; not medical advice. Consult a qualified professional before making health decisions.

How this is calculated

Weekly sleep debt

Debt = (sleep need − average sleep) × 7 nights

Catching up

Nights ≈ debt ÷ 1 extra hour a night

Need defaults to 8 hours (adults under 65) or 7.5 hours (65+), the middle of the recommended range. Set your own if you know it.

Sources

  • Hirshkowitz M et al. (2015), National Sleep Foundation's sleep time duration recommendations: methodology and results summary. Sleep Health 1:40–43.
  • Van Dongen HPA et al. (2003), The cumulative cost of additional wakefulness: dose-response effects on neurobehavioral functions and sleep physiology from chronic sleep restriction and total sleep deprivation. Sleep 26:117–126.

About the sleep debt calculator

What sleep debt is

Sleep debt is the gap between the sleep you need and the sleep you get, added up over days. In lab studies, people limited to 6 hours a night for two weeks performed as badly on attention tests as people kept awake for a night, yet rated themselves only slightly sleepy.

Read more about the Sleep Debt calculator

Paying it back

You can't bank sleep in advance, but you can recover over several nights with earlier nights or the odd lie-in of an hour or so. Long weekend lie-ins shift your body clock and make Monday harder. If you sleep enough but still feel exhausted, speak to a doctor.

Frequently asked questions

Can you catch up on lost sleep?

Partly. A few nights of extra sleep restore alertness, but long-term short sleep has costs that catching up doesn't fully undo.

How much sleep do I need?

Most adults need 7–9 hours. If you wake without an alarm feeling rested on holiday, that's a good guide to your need.

Do naps help with sleep debt?

A 20-minute nap early in the afternoon helps alertness. Longer or later naps can make night sleep harder.