Select your age group and time to see optimal sleep and wake-up windows.
Sleep Needs by Age
Adults need 7 or more hours of sleep a night (CDC and the American Academy of Sleep Medicine). For a 7:00 AM alarm that means lights out at 11:15 PM for five 90-minute cycles or 9:45 PM for six, allowing 15 minutes to fall asleep. Children need more. Pick an age group above and the calculator lists bedtimes that end on a full cycle.
Sleep requirements change dramatically from birth through adulthood. Children need significantly more sleep than adults, and their sleep cycles are shorter. The table below shows current National Sleep Foundation recommendations for each age group.
| Age Group | Hours Needed | Cycle Length | Notes |
|---|---|---|---|
| 👶 Newborn (0-3 mo) | 14-17 hrs | ~50-60 min | Distributed day & night |
| 👶 Infant (4-11 mo) | 12-15 hrs | ~60 min | Includes 2-3 naps |
| 🧒 Toddler (1-2 yrs) | 11-14 hrs | ~60-70 min | Includes 1 afternoon nap |
| 🧒 Preschool (3-5 yrs) | 10-13 hrs | ~70-80 min | Nap optional after age 4 |
| 🧒 School Age (6-13 yrs) | 9-11 hrs | ~80-90 min | No naps typically |
| 📱 Teen (14-17 yrs) | 8-10 hrs | 90 min | Circadian shift = later sleep |
| 👨 Young Adult (18-25) | 7-9 hrs | 90 min | NSF optimal range |
| 👨 Adult (26-64) | 7-9 hrs | 90 min | NSF optimal range |
| 👴 Senior (65+) | 7-8 hrs | 90 min | More frequent waking |
Why Children Need More Sleep
Children's brains are undergoing rapid development. During deep sleep, the brain consolidates memories from the day, produces growth hormone, and clears metabolic waste products. Children spend a higher proportion of sleep in slow-wave (deep) sleep than adults, which is why adequate sleep duration is especially critical in the first 12 years.
Unlike adults who become sleepy when sleep-deprived, children often become more hyperactive. This means parents frequently misread sleep deprivation as excess energy. A consistently overtired school-age child may show behavioral problems, difficulty concentrating, and emotional dysregulation rather than obvious sleepiness.
The 90-Minute Sleep Cycle Explained
Adults move through four sleep stages in a cycle of roughly 90 minutes: N1 (light sleep), N2, N3 (deep slow-wave sleep), usually back to N2, then REM (rapid eye movement). Waking at the end of a complete cycle, when sleep is naturally lightest, minimizes grogginess. Waking in the middle of N3 deep sleep causes sleep inertia, a groggy spell that usually fades within 15 to 30 minutes but can last up to an hour.
Children have shorter cycles. Newborn cycles are approximately 50-60 minutes. By age 5-6, cycles begin approaching the adult 90-minute duration. This calculator adjusts the cycle length per age group to give accurate recommendations across all ages.
Sleep Hours by Age: CDC and AASM vs NSF
Two sets of numbers are in common use. CDC publishes the American Academy of Sleep Medicine (AASM) consensus ranges; the calculator above uses the National Sleep Foundation (NSF) ranges, which group ages slightly differently. For children under 6 the hours include naps.
| Age | CDC / AASM | NSF (2015) |
|---|---|---|
| Newborn, 0 to 3 months | 14 to 17 hours | 14 to 17 hours |
| Infant, 4 to 12 months | 12 to 16 hours | 12 to 15 hours (4 to 11 months) |
| Toddler, 1 to 2 years | 11 to 14 hours | 11 to 14 hours |
| Preschool, 3 to 5 years | 10 to 13 hours | 10 to 13 hours |
| School age, 6 to 12 years | 9 to 12 hours | 9 to 11 hours (6 to 13) |
| Teen, 13 to 17 years | 8 to 10 hours | 8 to 10 hours (14 to 17) |
| Adult, 18 to 60 years | 7 or more hours | 7 to 9 hours (18 to 64) |
| Adult, 61 to 64 years | 7 to 9 hours | 7 to 9 hours |
| 65 and older | 7 to 8 hours | 7 to 8 hours |
CDC takes the newborn range from the NSF, since the AASM consensus starts at 4 months.
Bedtimes for a 7:00 AM Wake-Up by Age
The calculator's optimal options with 15 minutes to fall asleep and no nap. Night sleep for young children is shorter than the daily total because naps make up the rest.
| Age group | Cycle used | Bedtime | Night sleep |
|---|---|---|---|
| Infant, 4 to 11 months | 60 min | 7:45 PM or 8:45 PM | 11 or 10 hours |
| Toddler, 1 to 2 years | 65 min | 6:50 PM or 7:55 PM | 11.9 or 10.8 hours |
| Preschool, 3 to 5 years | 75 min | 7:30 PM or 8:45 PM | 11.25 or 10 hours |
| School age, 6 to 13 years | 85 min | 8:50 PM | 9.9 hours |
| Teen, 14 to 17 years | 90 min | 9:45 PM | 9 hours |
| Adult, 18 to 64 years | 90 min | 9:45 PM or 11:15 PM | 9 or 7.5 hours |
| 65 and older | 90 min | 11:15 PM | 7.5 hours |
Children's cycle lengths are approximations; the total hours matter more than landing exactly on a cycle. Adults who want more wake-up options by bedtime can use the sleep cycle calculator.
Habits That Help You Reach Those Hours
- Keep the same wake time every day, weekends included. It anchors your body clock more than any single bedtime.
- Make the bedroom dark, quiet and cool, and keep phones and TVs out of it, especially for children and teens.
- Stop caffeine by early afternoon and avoid alcohol and large meals close to bedtime.
- Get daylight and exercise during the day, but finish hard workouts a few hours before bed.
If you regularly sleep the recommended hours and still wake up tired, snore loudly or stop breathing in your sleep, talk to a doctor. For a child's sleep concerns, ask your pediatrician. These results are general estimates, not medical advice.