Sleep Cycle

Sleep by age

How much sleep do you need?

Sleep needs change across a lifetime. Pick your age group to see the recommended range — then use the calculator to land it at a clean sleep cycle.

Your age group
7–9 hours / night

Recommended sleep by age

Based on the National Sleep Foundation's consensus recommendations. Children's totals include naps.

Age groupRecommended
"Sleep need" vs "time in bed"
Recommendations are actual sleep, not time in bed. If you take 15 minutes to fall asleep, add that to your schedule.
The 6-hour illusion
Many adults feel fine on 6 hours but perform measurably worse — the brain adapts its sense of tiredness, not its actual impairment.

Common questions

How much sleep do I need by age?

Newborns 14–17h, infants 12–15h, toddlers 11–14h, preschoolers 10–13h, school-age 9–11h, teens 8–10h, adults 7–9h, older adults 7–8h.

Is 6 hours enough for an adult?

For most adults, no. The recommendation is 7–9 hours. People who routinely sleep 6 hours score worse on cognitive tests even when they feel adapted.

Do older adults need less sleep?

Only slightly — about 7–8 hours. They sleep lighter and wake more, but still need a similar total; chronic short sleep raises health risks at any age.

References & method · 参考来源与方法

Ranges follow the National Sleep Foundation consensus recommendations (Hirshkowitz et al., 2015). This tool is for general use and is not medically reviewed; consult a professional for sleep concerns. Sources: National Sleep Foundation (NSF); American Academy of Sleep Medicine (AASM); CDC — sleep.

Now turn hours into a bedtime

Knowing your target hours is step one. The calculator turns it into a specific bedtime aligned to 90-minute sleep cycles.

Sleep calculator → Nap calculator →