How Much Sleep Do I Need? A Complete Guide by Age

Q: Do naps count toward total sleep?

Short naps (20-30 minutes) can help with alertness and do not typically interfere with nighttime sleep. Longer naps or naps taken late in the afternoon can make it harder to fall asleep at night. For adults, the National Sleep Foundation recommends limiting naps to 20-30 minutes before 3 PM.

Updated March 2026 · 9 min read · By Travis Cook

Sleep isn't optional. It affects your mood, memory, immune system, weight, heart health, and how long you live. Yet roughly one in three American adults doesn't get enough of it. How much you need depends mostly on your age, though some people genuinely need more or less than the average.

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Recommended Sleep by Age

The following recommendations come from the National Sleep Foundation and the American Academy of Sleep Medicine. These are totals per 24-hour period, including naps for younger children.

Age Group	Age Range	Recommended Sleep
Newborn	0-3 months	14-17 hours
Infant	4-11 months	12-15 hours
Toddler	1-2 years	11-14 hours
Preschool	3-5 years	10-13 hours
School Age	6-13 years	9-11 hours
Teenager	14-17 years	8-10 hours
Young Adult	18-25 years	7-9 hours
Adult	26-64 years	7-9 hours
Older Adult	65+ years	7-8 hours

Understanding Sleep Cycles

Sleep isn't a uniform state. You cycle through several stages multiple times per night, and each complete cycle takes approximately 90 minutes. A typical night includes 4-6 full cycles. The stages are light sleep (stages 1-2), deep sleep (stage 3, also called slow-wave sleep), and REM (rapid eye movement) sleep, where most dreaming occurs.

Ever wake up after 8 hours feeling worse than when you went to bed? That's because your alarm caught you in the middle of a deep sleep cycle. The grogginess is called sleep inertia, and it's brutal. Waking up at the end of a cycle feels completely different. That's why 7.5 hours (5 complete cycles) can actually feel better than 8 hours if the extra 30 minutes lands you mid-cycle. The Sleep Calculator helps you time your bedtime and wake time to align with these natural cycles.

Caffeine and Sleep

Caffeine has a half-life of approximately 5-6 hours, meaning half the caffeine from your afternoon coffee is still in your system 5-6 hours later. A quarter of it remains after 10-12 hours. For most adults, the general guideline is to stop consuming caffeine at least 8 hours before bedtime. If you go to bed at 10 PM, your last coffee should be before 2 PM.

Some people metabolize caffeine fast (lucky them) and some people are still wired from a morning cup at midnight. It's genetic. If you suspect caffeine is the problem even when you cut it off early, try our Caffeine Calculator to track how much is still in your system at bedtime.

Signs You Are Not Getting Enough Sleep

Sleep deprivation doesn't always feel like you're tired. It sneaks up on you. You need an alarm every single morning. You zone out in meetings. You can't function after lunch without coffee. You fall asleep within 5 minutes of hitting the pillow (that's actually a sign of deprivation, not being a "good sleeper" -- healthy sleep onset takes 10-20 minutes). You're more irritable than usual. You catch every cold that goes around.

Evidence-Based Tips for Better Sleep

Keep a consistent schedule. Go to bed and wake up at the same time every day, including weekends. This is the single most impactful change for most people. Create a cool, dark, quiet room. Ideal sleep temperature is 60-67F (15-19C). Use blackout curtains and consider earplugs or a white noise machine. Limit screens before bed. Blue light from phones and computers suppresses melatonin production. Stop screen use 30-60 minutes before bed, or use a blue light filter. Watch your caffeine. Cut off caffeine 8+ hours before bed. Avoid alcohol close to bedtime. Alcohol helps you fall asleep faster but fragments sleep in the second half of the night, reducing sleep quality. Get morning sunlight. Exposure to bright light within the first hour of waking helps set your circadian rhythm and makes falling asleep easier at night.

Sleep and Exercise

Exercise helps you sleep better. That's not controversial. Even a brisk walk improves deep sleep and helps you fall asleep faster. The only caveat: intense workouts within 1-2 hours of bedtime can wire some people up. Morning or afternoon sessions tend to have the best payoff for nighttime sleep.

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About the Author

Travis Cook writes about health and wellness for MayoCalc. With a background in radiology and clinical imaging, Travis translates peer-reviewed medical research into practical guidance backed by data from the ADA, AHA, ACC, and CDC. All health content is sourced and linked so you can verify every claim.

Sleep FAQ

Is 6 hours of sleep enough?

For the vast majority of adults, no. Research consistently shows that sleeping less than 7 hours per night is associated with increased risk of obesity, diabetes, cardiovascular disease, and impaired cognitive function. A very small percentage of people (less than 1%) carry a genetic mutation that allows them to function well on 6 hours, but most people who think they're fine on 6 hours have simply adapted to feeling chronically tired.

Can I catch up on sleep over the weekend?

Partially. Sleeping extra on weekends can help recover from short-term sleep debt, but it doesn't fully reverse the health effects of chronic sleep deprivation. It can also disrupt your circadian rhythm, making Monday mornings even harder. A consistent daily schedule is more effective than weekend catch-up.

Why do I wake up at 3 AM?

Waking in the middle of the night is common and often caused by stress, alcohol consumption, blood sugar fluctuations, room temperature, or needing to use the bathroom. If it happens occasionally, it's normal. If it happens frequently and you can't fall back asleep within 15-20 minutes, talk to your doctor about possible underlying causes.

Do naps count toward total sleep?

Short naps (20-30 minutes) can help with alertness and don't typically interfere with nighttime sleep. Longer naps or naps taken late in the afternoon can make it harder to fall asleep at night. For adults, the National Sleep Foundation recommends limiting naps to 20-30 minutes before 3 PM.

Does screen time really affect sleep?

Yes. The blue light emitted by phones, tablets, and computers suppresses melatonin production, which is the hormone that signals your body it's time to sleep. Studies show that using screens within an hour of bedtime delays sleep onset and reduces sleep quality. If you must use screens, enable a blue light filter or wear blue-light-blocking glasses.

For more on this topic, see our caffeine guide and our resting heart rate guide.

For more on this topic, see our hydration guide.

Sources

National Sleep Foundation: Sleep duration recommendations by age group
Centers for Disease Control and Prevention (CDC): CDC recommended hours of sleep by age

Related Tools

Find your ideal bedtime with the Sleep Calculator. Track caffeine in your system with the Caffeine Calculator. Monitor your overall health with the BMI Calculator and Calorie Calculator.

Disclaimer: This article is for educational purposes only. Sleep recommendations are based on guidelines from the National Sleep Foundation and the American Academy of Sleep Medicine. If you are experiencing persistent sleep problems, consult a healthcare provider.