Sleep Hours by Age Calculator

The American Academy of Sleep Medicine (AASM) and the National Sleep Foundation (NSF) both recommend 7–9 hours of sleep per night for adults aged 18–64. The CDC endorses 7+ hours as the minimum. Older adults (65+) typically need 7–8 hours, though natural age-related changes mean they often get less consolidated sleep.

Newborns need 14–17 hours because sleep is when the brain does the majority of its rapid development. During sleep, synaptic pruning, myelination, and neural pathway formation accelerate. REM sleep — which constitutes up to 50% of infant sleep versus 20–25% in adults — drives most of this neural construction.

Yes. Teenagers need 8–10 hours per night, and this is a genuine biological requirement — not laziness. Adolescent brains undergo a second major developmental phase, and the circadian clock shifts 2–3 hours later during puberty. Chronic sleep deprivation in teenagers is associated with depression, poor academic performance, obesity, and increased accident risk.

True short sleepers — people who function optimally on 6 or fewer hours due to a genetic mutation (DEC2/ADRB1) — exist but constitute less than 3% of the population. The vast majority of people who believe they need only 6 hours are sleep-deprived and habituated to impaired functioning, as demonstrated in multiple lab studies showing their performance on objective tests is significantly impaired.

Total sleep need decreases modestly across the lifespan — from 16+ hours as a newborn to 7–8 hours in adulthood — but the change from young adult to older adult is small (roughly 30 minutes less). What changes more significantly is sleep architecture (less deep sleep, more fragmentation) and sleep timing (earlier phase shift). Older adults who get only 5–6 hours are not necessarily meeting their sleep need.

Chronic sleep restriction to even 6 hours per night (versus the recommended 7–9) produces progressive cognitive impairment equivalent to 24 hours of total sleep deprivation within 2 weeks, as shown in Van Dongen's landmark lab studies. The insidious aspect is that sleep-deprived individuals consistently underestimate their impairment level — they adapt to feeling 'fine' while performing measurably worse.