Child Sleep Requirements Calculator
Calculates recommended total sleep duration and a suggested bedtime for children based on age, desired wake time, nap duration, and daily activity level. Use it to set healthy sleep routines from infancy through the teenage years.
About this calculator
Recommended sleep totals decrease as children age: under 1 year needs ~14 hours, ages 1–2 need ~12 hours, ages 3–5 need ~11 hours, ages 6–12 need ~10 hours, and teenagers need ~9 hours. The calculator adds a nap adjustment — every 60 minutes of daytime napping contributes 0.5 hours to the total sleep need (since naps partially substitute for, but do not fully replace, night-time sleep). Activity level adds 0.5 hours for highly active children or subtracts 0.5 hours for low-activity children. Bedtime is calculated by subtracting the total sleep need from the desired wake time: bedtime = wakeTime − totalSleep, floored at a minimum of 9 hours' sleep. Formula: bedtime (24 hr) = wakeTime − max(9, baseHours + napAdjust + activityAdjust).
How to use
A 4-year-old (base = 11 hours) takes a 30-minute nap (napAdjust = 0.5 × 0.5 = 0.25 hours) and has a high activity level (activityAdjust = +0.5). Total sleep = 11 + 0.25 + 0.5 = 11.75 hours. Desired wake time = 7:00 (24-hr value 7). Bedtime = 7 − 11.75 = −4.75, which wraps to 19:15 the previous evening — i.e., a 7:15 PM bedtime. Enter these numbers into the calculator and it will display the formatted bedtime directly.
Frequently asked questions
How many hours of sleep does a child need by age?
The American Academy of Sleep Medicine recommends 12–16 hours (including naps) for infants 4–12 months, 11–14 hours for toddlers 1–2 years, 10–13 hours for preschoolers 3–5 years, 9–12 hours for school-age children 6–12 years, and 8–10 hours for teenagers 13–18 years. These ranges reflect the steep decline in sleep need as the brain matures. Consistently falling below the lower end of the range is associated with attention problems, mood difficulties, and impaired immune function.
Why does a high activity level increase how much sleep a child needs?
Physical activity promotes deeper, more restorative slow-wave sleep, and children who are highly active during the day typically need slightly more total sleep to support muscle repair, growth hormone release, and memory consolidation. Studies show that active children fall asleep faster and spend more time in deep sleep stages. The additional 30-minute adjustment in this calculator is a modest reflection of that relationship — it should be seen as a guideline rather than a precise prescription.
When should children stop napping and how does this affect their bedtime?
Most children naturally phase out daytime naps between ages 3 and 5, though some 6-year-olds still benefit from a short rest. When naps are dropped, the lost daytime sleep must be compensated by an earlier bedtime — usually 30–60 minutes earlier than when the child was still napping. Signs a child is ready to drop the nap include consistently taking more than an hour to fall asleep at nap time, resisting naps for several weeks, and having no trouble staying alert through the afternoon without one.