How Much Sleep Do I Need? An Age-by-Age Guide
"Get eight hours" is the most repeated sleep advice on the planet — and also the least useful. Your real number depends on your age, your genes, and how hard you ran your body and brain that day. Here's the actual range, and how to find yours.
The official recommendations
These are the consensus ranges from major sleep and health authorities. Treat them as a target band, not a single magic number:
- Newborns (0–3 mo): 14–17 hours
- Infants (4–11 mo): 12–15 hours
- Toddlers (1–2 yr): 11–14 hours
- Preschool (3–5 yr): 10–13 hours
- School-age (6–12 yr): 9–12 hours
- Teenagers (13–18 yr): 8–10 hours
- Adults (18–64 yr): 7–9 hours
- Older adults (65+): 7–8 hours
Why it's a range, not a rule
Two people the same age can need an hour apart. "Short sleepers" with a specific gene variant feel fine on 6 hours; most of us don't have it. The range exists because biology isn't a spreadsheet.
What shifts your personal number
- Genetics: A small percentage are true short or long sleepers — everyone else is just undersleeping.
- Physical training: Hard exercise, especially endurance work, raises recovery needs temporarily.
- Stress and illness: Healing and high cortisol both demand more sleep.
- Pregnancy: The first trimester often adds a strong daytime pull toward sleep.
- Sleep quality: Fragmented, apnea-broken sleep means you need more time in bed to get the same recovery.
5 signs you're under-sleeping
You don't need a wearable to know. Watch for:
- Needing an alarm to wake up (and hitting snooze).
- Falling asleep within minutes of lying down.
- Afternoon crashes around 2–4 p.m.
- Reaching for caffeine after noon just to function.
- Irritability and brain-fog by evening.
Quality matters as much as quantity
Seven hours of continuous, well-cycled sleep beats nine hours of tossing. That's why timing your wake-up to the end of a cycle — instead of mid-deep-sleep — changes how you feel far more than an extra 30 minutes jammed on top.
Find your number
Start from your age band, then nudge based on the signs above. A simple way to test: pick a wake-up time, work back through 90-minute cycles, and see how you feel after a week.
Frequently asked questions
How many hours of sleep do adults need?
7-9 hours is the recommended range for adults 18-64, with 7-8 hours often being the "sweet spot" for most. Under 6 hours or over 10 hours is associated with increased mortality and cardiovascular risk in studies.
Is 6 hours of sleep enough?
For a small minority of people with the DEC2 gene mutation, yes — but they're less than 5% of the population. For everyone else, 6 hours is associated with cumulative cognitive deficit, even if you feel "fine." Subjective adaptation is not the same as actual performance.
How much sleep do teenagers need?
8-10 hours, with 9 hours being average. Teens need more sleep than adults because their brains are still developing, especially the prefrontal cortex. Most teen sleep deprivation comes from early school start times, not lack of opportunity.
Can I catch up on sleep on weekends?
Partially. "Sleep banking" — extra sleep on weekends — recovers about 1 hour of the weekly deficit. But it doesn't reverse the metabolic and cognitive impacts of weekday sleep loss, and shifting your schedule by 2+ hours creates social jet lag that hurts Monday-Wednesday sleep.
Do older adults need less sleep?
Sleep need stays roughly constant across adulthood. What changes is sleep ability — older adults get less deep sleep and more fragmented sleep. The recommendation remains 7-8 hours, even if it's harder to achieve.
References
- Hirshkowitz, M., et al. (2015). National Sleep Foundation's sleep time duration recommendations. Sleep Health, 1(1), 40–43.
- American Academy of Sleep Medicine. (2021). Consensus Statement on Sleep Duration. sleepeducation.org.
- Centers for Disease Control and Prevention. (2022). How Much Sleep Do I Need? cdc.gov.