How Much Sleep Do I Need? Calculator
See how much sleep you need by age using National Sleep Foundation ranges, with recommended hours and a deep and REM sleep breakdown for a typical night. Free, no signup.
For babies under a year, switch to months for the right band.
Approximate stage split — real proportions vary night to night.
Aim to be asleep between 10:00 PM and 12:00 AM. For the sweet spot, target 11:00 PM.
That's below the recommended 7–9 hours for your age — about 0.5 hours short of the minimum. Regularly under-sleeping builds up as sleep debt.
How much sleep you need by age
There is no single magic number — how much sleep you need changes across life. The most widely used guidance comes from the National Sleep Foundation, whose expert panel reviewed hundreds of studies to set recommended ranges for each age band: 14–17 hours for newborns, tapering down through childhood to 8–10 hours for teenagers and 7–9 hours for adults, then a slightly lower 7–8 hours for older adults. The ranges are wide on purpose — within any age group, some people genuinely need more sleep than others. The tool above picks your band, shows that range, and marks a "sweet spot" near the middle as a sensible target to aim for.
Deep sleep vs REM: how a night is structured
A night isn't one flat block of sleep — it's a series of ~90-minute cycles, four to six of them, each moving through light sleep, deep (slow-wave) sleep, and REM. The mix shifts as the night goes on: deep sleep dominates the early cycles and handles physical repair, while REM — where most dreaming and memory consolidation happen — gets longer toward morning. In a typical adult night, light sleep is about half the total, deep sleep roughly 13–23%, and REM around 20–25%, with a few brief awakenings that are completely normal. Because REM is back-loaded, cutting your night short by even an hour strips away a disproportionate slice of it — which is one reason total sleep time matters as much as sleep quality.
The stage breakdown above applies those typical percentages to your target hours so you can see roughly how much deep and REM sleep a full night should contain. You can't consciously control the split, but you can protect it: keep a steady schedule, limit late caffeine and alcohol, and give yourself enough time in bed. For more, see the sleep hygiene checklist.
The single most powerful lever for hitting your range is a consistent bedtime — going to bed at roughly the same time every night trains your body clock so you fall asleep faster and get more complete cycles. That's exactly the kind of thing worth tracking as a daily habit. HabitBox lets you log a one-tap "in bed by my target time" check-in each night and watch the streak build; it's free, works on iOS and Android, and keeps all your data on-device with no account needed.
Note: these are general guidance ranges for healthy people, not medical advice. Persistent trouble sleeping, excessive daytime sleepiness, or a sleep disorder are worth discussing with a clinician.
Frequently asked questions
How much sleep do I need by age?+
The National Sleep Foundation recommends 7–9 hours for adults (18–64), 7–8 hours for older adults (65+), 8–10 hours for teens (14–17), and 9–11 hours for school-age children (6–13). Younger children need more: 10–13 hours for preschoolers, 11–14 for toddlers, and 12–17 for infants and newborns. Enter your age above to see your exact range and a target sweet spot.
How much deep sleep do I need?+
Deep (slow-wave) sleep typically makes up about 13–23% of a healthy adult's night, so roughly 1 to 2 hours if you sleep 7–9 hours. Deep sleep is when the body does most of its physical repair, and it's concentrated in the first half of the night. You can't force more of it directly, but going to bed at a consistent time and protecting total sleep are the most reliable ways to get enough.
How much REM sleep do I need?+
REM sleep — the dreaming, memory-consolidating stage — usually accounts for about 20–25% of a night, or roughly 1.5 to 2 hours for an adult sleeping 7–9 hours. REM cycles get longer toward morning, which is why cutting sleep short or waking early can disproportionately rob you of REM. Consistent full nights are the way to protect it.
Is 6 hours of sleep enough?+
For almost all adults, no. Six hours falls below the recommended 7–9 hour range, and the small fraction of people who genuinely function well on six is far smaller than the number who think they do. Regularly sleeping six hours or less is linked to reduced attention, mood, and long-term health outcomes. If six is your norm, treat it as an accumulating sleep debt to address.
Is 7 hours of sleep enough?+
For most adults, yes — 7 hours sits at the bottom of the recommended 7–9 hour range and is enough for many people. The right amount within that range is individual: if you wake refreshed, stay alert without heavy caffeine, and don't crash in the afternoon, seven is likely fine. If you feel you need an alarm to wake and drag through mornings, you may do better closer to 8 or 9.
Does sleep need change with age?+
Yes. Sleep need is highest in infancy and childhood and gradually decreases into adulthood, where it stabilizes at 7–9 hours through most of adult life. Older adults (65+) need a touch less, around 7–8 hours, and often experience lighter, more fragmented sleep with less deep sleep — but the total requirement doesn't drop dramatically. Needing far less sleep in old age is a myth.
Make a consistent bedtime automatic
Knowing your target range is step one. Actually getting to bed on time, night after night, is what changes how you feel. HabitBox turns 'in bed by my target' into a one-tap daily habit — free, on-device, no account, on iOS and Android.
Free · Local-only data · No account required