Sleep Debt Calculator

Sleep debt is the gap between the sleep you need and the sleep you get, added up over several nights. It is not a diagnosis, and there is no clinical unit for it. This calculator gives a simple tally of missed sleep for the past week.

What Sleep Debt Measures

It measures missed time asleep, in hours and minutes, against a target. It does not measure how well you slept, how sleepy you feel, or your health. It also cannot tell how much of the loss your body has already made up.

The Formula

Shortfall for one night = Sleep need - Time asleep (0 if you met your need)

Sleep debt = Shortfalls from each night added together

Average shortfall per night = Sleep debt / Number of nights entered

The default sleep need is the minimum from the American Academy of Sleep Medicine (AASM) statements on how much sleep adults and children need¹ ².

How This Calculator Computes Your Result

Choose your age group, or enter your own sleep need. Then enter your time asleep for each of the last 7 nights, or one weekly average. Enter time asleep, not time in bed, and leave out naps. Blank nights are skipped.

The child and teen figures come from the AASM pediatric statement, endorsed by the American Academy of Pediatrics². The adult figure comes from the AASM and Sleep Research Society statement for ages 18 to 60¹, and the National Sleep Foundation's ranges for older adults also start at 7 hours³. Children under 6 are not included, because naps count toward their sleep².

Using the low end of each range keeps the tool from overstating your debt. If you only feel rested after 8 hours, enter 8 as your own need.

Extra sleep on a long night is shown on its own line and does not reduce your debt. You also see your average shortfall per night and how many nights fell short. Night by night entry is the default because an average can hide short nights. A week of 6 h 30 min, 6 h, 7 h 15 min, 5 h 45 min, 6 h 30 min, 8 h 30 min and 9 h averages just over 7 hours, yet holds 3 h 15 min of debt.

What Your Result Means

In adults, regularly sleeping less than 7 hours is linked with weight gain, diabetes, high blood pressure, heart disease, stroke, depression and a higher risk of death¹. In children and teens, too little sleep is linked with attention, behavior and learning problems². There is no agreed scale for a "large" sleep debt, so the tool does not grade the size of your number. The AASM advises that people concerned they are sleeping too little or too much should talk with a healthcare provider¹.

Why Short Nights Add Up

In a lab study of 48 healthy adults, some spent 4, 6 or 8 hours in bed each night for 14 days and others went 3 nights without sleep⁴. Those limited to 6 hours or less got steadily worse on attention and thinking tests, reaching deficits similar to up to 2 nights with no sleep at all⁴. Their sleepiness ratings rose at first, then changed little, so they seemed largely unaware of how impaired they were⁴. A written tally can catch what you do not feel.

Can You Catch Up on Sleep Debt?

One or two long nights may not reset everything. In a study of 66 adults, people kept to 3, 5 or 7 hours in bed for 7 nights had not returned to their starting performance after 3 nights of 8 hours in bed⁵. In a 2 week lab study of 36 healthy adults, sleeping in on the weekend did not prevent a drop in insulin sensitivity (how well the body uses insulin to control blood sugar) on a schedule of 5 hour weeknights⁶.

These small lab studies cannot say how much catch-up sleep you need, but they are why this tool does not subtract extra sleep from your debt. To plan bedtimes for the week ahead, use the Sleep Calculator.