Sleep Calculator by Age

Sleep calculator for kids and adults that calculates when to go to bed based on your age, sleep cycles, and desired wake-up time.

What time do you want to wake up?

Age: 25

Going to bed now?

Your Results

To wake up at 6:30 AM feeling refreshed, you should go to sleep at:

Recommended

11:00PM

7.5 hours, 5 sleep cycles

Try this for 3-5 nights. If still tired after 3-5 consistent nights, increase by one full cycle to:

Alternative

9:30PM

9 hours, 6 sleep cycles

Most people take about 15 minutes to fall asleep (this is factored into your times).

Adults aged 18-25 typically need 7-9 hours of sleep per night.

A good night's sleep consists of complete 90-minute sleep cycles. Waking between cycles helps you feel more refreshed.

How to Use the Sleep Calculator by Age

Use the sleep calculator to find out what time you should go to bed so you wake up feeling refreshed.

How to use:

Choose the time you want to wake up using the time selector.
Select your age using the slider so the calculator can apply accurate, age-based sleep recommendations.
Click “Calculate Bedtime” to see the best time to go to sleep based on your age and complete sleep cycles.

You’ll see two bedtime options:

Recommended: The optimal bedtime based on your age and sleep cycles
Alternative: A slightly longer sleep option to try if you still feel tired

Follow the recommended bedtime consistently for a few nights to see how you feel.

The calculator uses average 90-minute sleep cycles and age-based sleep needs to help you wake up feeling refreshed instead of groggy. It also factors in an average 15-minute wind-down period, which is how long most people take to fall asleep.

Going to bed right now? Use the “Calculate Wake-Up Time” option to see when to wake up at the end of a full sleep cycle.

How This Sleep Calculator Works

The sleep calculator helps you wake up feeling refreshed by timing your sleep around complete sleep cycles, not just counting hours.

Your body moves through roughly 90-minute sleep cycles, each passing through light sleep, deep sleep, and REM sleep. Waking up mid-cycle, especially during deep sleep, leaves you groggy and sluggish. Waking up between cycles helps you feel sharper and more energized.

The sleep calculator works by finding ideal bedtimes based on your wake-up time and age. Your sleep needs shift throughout life. For example, teenagers need more sleep than adults, while older adults often need slightly less than younger adults.

The age selector helps fine-tune the recommendation to you.

Each suggested bedtime accounts for a 15-minute wind-down period, which is the average time it takes to actually fall asleep after getting into bed.

These times are practical starting points. But the key is consistency. Stick with a consistent sleep schedule for a few nights, and your body will settle into a healthier rhythm that works for you.

If you need more or less sleep based on how you feel after a consistent sleep schedule, you can make adjustments

Recommended Sleep Duration by Age

Sleep needs vary by individual, but these ranges provide a general guideline based on age.

Age Group	Age Range	Recommended Sleep Per Day (includes naps)
Newborns	0-3 months	14-17 hours
Infants	4-12 months	12-16 hours
Toddlers	1-2 years	11-14 hours
Preschool children	3-5 years	10-13 hours
School-age children	6-12 years	9-12 hours
Teenagers	13-18 years	8-10 hours
Adults	18-64 years	7-9 hours
Elders	65+ years	7-8 hours

Frequently Asked Questions

Sleep calculators by age are useful guidelines but not perfectly accurate. They provide a good starting point based on general recommendations, but can oversimplify sleep needs. Individual sleep requirements vary based on factors like genetics, lifestyle and health habits. Sleep calculators work best when combined with consistent sleep habits and taken as a solid starting point, not rigid rules.

Most healthy adults fall asleep within 15 to 20 minutes. Taking less than 5 minutes can be a signal of sleep deprivation, while taking over 20 minutes may point to other sleep issues. The time it takes to fall asleep is called “sleep latency”, and the exact length varies from person to person.

Sleep cycles matter when choosing a bedtime because waking up at the end of the 90-minute cycle helps you feel more refreshed. The end of the cycle is generally during lighter sleep, while waking up in the middle of a cycle during deep sleep can lead to grogginess. Consistent sleep routines and cycles support your body’s internal clock (circadian rhythm), which can lead to better energy, mood and even general health.

Feeling tired even after 8 hours of sleep means your sleep isn’t restorative. This can be due to issues such as a disrupted circadian rhythm (inconsistent schedule), poor sleep habits (screen time before bed, caffeine, alcohol, noisy room), underlying stress/anxiety, or medical conditions like sleep apnea, anemia, or vitamin deficiencies. Sleep is about quality, not quantity. The key is to create a consistent routine, a cool/dark room, a healthy diet, and managing stress to get true rest. If you still aren’t sleeping well, contact a professional and get medical support.

The amount of sleep you need shifts throughout your life. Newborns require the most at 14-17 hours, while school-aged kids need 9-12 hours, and teens need 8-10. Most adults do best with 7-9 hours, and older adults (65+) still generally need 7-8 hours for optimal health.

Yes, sticking to a consistent sleep schedule, even on weekends, is one of the best things you can do for your sleep. Going to bed and waking up at the same time regulates your circadian rhythm, improves sleep quality, and supports better mental and physical health. A fixed wake-up time is especially important. It builds natural sleep pressure throughout the day and helps prevent Sunday night insomnia when your weekend schedule throws off your rhythm.

Yes, waking up naturally is generally better for you. It allows your body to complete sleep cycles on its own terms, which reduces sleep inertia (that groggy feeling), lowers stress hormones, and leads to more restful sleep overall. You’re also more likely to wake during a lighter sleep stage, making the transition smoother and leaving you in a better mood. That said, alarms are sometimes necessary. The key is using them consistently so your body can anticipate the wake-up time.

A sleep calculator cannot replace professional medical advice, diagnosis, or treatment. These tools provide general guidance and are intended for informational purposes only.