How much sleep do I need?
If you're an adult: 7–9 hours, with 8 hours as the planning target — the National Sleep Foundation's consensus range for ages 26–64. The exact range depends on age, and the calculator below gives you yours from the NSF's published table, lets you pick a personal target within it, and turns that into a bedtime.
Drag to tune — the midpoint is a good start.
Age band
Adult
26–64 years
Recommended range
7–9 h
per 24 hours, naps included for under-5s
Your working target
8 h
bedtime = wake time − 8 h − time to fall asleep
the arithmetic · midpoint of 7–9 h = 8 h
Ranges: National Sleep Foundation, 2015. If you consistently feel good on a value just outside the range, that's data — but persistent short sleep below the "may be appropriate" floor is a health risk, not a productivity hack.
Planning tool, not medical advice. These figures are population averages for scheduling your sleep — they don't diagnose or treat any condition. See a clinician for persistent sleep problems.
How much sleep is recommended for each age?
Source: National Sleep Foundation's updated sleep duration recommendations (Hirshkowitz et al., Sleep Health, 2015), the consensus of an 18-member expert panel convened from 12 stakeholder organisations that reviewed 300+ studies. "May be appropriate" is the panel's own outer envelope for healthy individuals.
| Age band | Age | Recommended | May be appropriate |
|---|---|---|---|
| Newborn | 0–3 months | 14–17 h | 11–19 h |
| Infant | 4–11 months | 12–15 h | 10–18 h |
| Toddler | 1–2 years | 11–14 h | 9–16 h |
| Preschool | 3–5 years | 10–13 h | 8–14 h |
| School age | 6–13 years | 9–11 h | 7–12 h |
| Teenager | 14–17 years | 8–10 h | 7–11 h |
| Young adult | 18–25 years | 7–9 h | 6–11 h |
| Adult | 26–64 years | 7–9 h | 6–10 h |
| Older adult | 65+ years | 7–8 h | 5–9 h |
How do you find your number inside the range?
The range is population-level; your number is personal. Fix a steady wake time, go to bed early enough for 8 hours, and let yourself wake without an alarm for a week (holiday, not a work week). The average sleep you take when nothing is restricting it is your best available estimate. Track the trend with the sleep efficiency calculator — if efficiency runs over 90% and you still feel short, you need more time in bed, not more discipline.
What does chronic short sleep actually do?
The honest version, from the dose–response literature: two weeks of 6-hour nights builds cognitive impairment equivalent to one to two nights of total sleep deprivation, while subjective sleepiness plateaus — you lose the ability to notice your own decline. Long-term, habitual short sleep is associated in cohort studies with cardiovascular disease, metabolic dysfunction and weakened immune response. This is the one number on this site worth being boring about: get the hours.
FAQ
How much sleep do I need as an adult?
The National Sleep Foundation's 2015 consensus recommends 7–9 hours per night for adults aged 26–64, and 7–8 hours from 65 up. Young adults (18–25) get the 7–9 range with an explicit note that up to 11 may be appropriate. The midpoint — 8 hours — is the right planning target until you have evidence about yourself.
Can I train myself to need less sleep?
No. True short sleepers (functioning fully on under 6 hours) are a genetic rarity — a DEC2 mutation found in a handful of families — not an achievement. What training produces is habituation to the feeling of being under-slept: performance keeps declining while your self-assessment flattens. The dose–response studies (Van Dongen 2003) show exactly this dissociation.
Do teenagers really need that much?
Yes — 8–10 hours for 14–17-year-olds, per the same NSF panel. Adolescent biology also shifts timing later by up to two hours (the circadian delay of puberty), which is why school-start-time research keeps finding that later starts improve grades, mood and even traffic accident rates.
Is 6 hours of sleep enough?
For almost nobody as a standing schedule. Six hours sits below the “may be appropriate” floor (6 h) for adults and inside it only as an occasional night. Chronic 6-hour sleepers perform, after two weeks, like people who missed one to two full nights of sleep — while insisting they feel fine.
How we source this
The sleep-duration figures come from the National Sleep Foundation's 2015 consensus panel (Hirshkowitz et al., Sleep Health) — 18 experts convened from 12 stakeholder organisations, reviewing 300+ studies. The cycle, REM, jet-lag and wind-down models are built from the primary literature, and every source is listed with its context on the methodology & sources page.
Content is written and maintained by the SleepMaxx Calculator editorial team and checked against those sources. This site is not medically reviewed— no clinician reviews this content, and we would rather say that in plain text than hang a reviewer byline we don't have. These are planning tools built on population averages; for a personal sleep problem, a clinician is the right next step.
You will also not find an Epworth Sleepiness Scale, a STOP-BANG questionnaire or an AHI estimator here. Those are clinical screening instruments: their scores only mean something in the hands of someone who can act on them, and hosting them on a calculator site is a safety problem, not a feature. We exclude them deliberately.
Keep planning
Sleep Cycle Calculator
Bedtimes from a wake time, alarms from a bedtime — cycle length and latency as dials, not settings.
Bedtime Calculator
Enter your wake time — get the bedtimes that land you at the end of a sleep cycle.
Calculate Wake Up Time
Going to bed at a set time — get the alarms that land you at a cycle boundary.
90 Minute Sleep Cycle Calculator
The 90-minute rule applied properly — with the falling-asleep time most tools skip.