Sleep Need Calculator

Sleep need by age and activity level combines official guidelines with individual adjustment factors to estimate your optimal nightly sleep target.

Base sleep recommendations (National Sleep Foundation)

Every one of these nine bands is an option in the calculator, and these are the exact numbers it uses.

The “acceptable range” column is the panel’s own wording for what may still be appropriate for some individuals. It is not a target. If you are sleeping six hours and feeling fine, you are more likely mis-reading your own alertness than sitting at the edge of the distribution, for reasons the sleep debt section below explains.

Training load adjustment

Formula: Adjusted range = NSF range + training adjustment

This only applies from the teenage band upward. Younger children already sleep at the top of what their bodies will take, and their published ranges include naps, so adding to them makes no sense.

Worked example: A 34-year-old who trains intensely six days a week is in the Adults band at 7 to 9 hours, plus 60 minutes for a high training load, giving 8 to 10 hours with a midpoint of 9 hours. To wake at 7:00 AM that means asleep between 9:00 PM and 11:00 PM.

Sleep debt: Missed sleep accumulates. Research from the University of Pennsylvania found that sleeping 6 hours a night for two weeks produced cognitive impairment comparable to two full nights without any sleep, and the striking part is that the subjects rated their own sleepiness as only slightly elevated. Self-assessment fails exactly when you need it. Recovery takes several full nights, not one long weekend lie-in.