A word before the numbers. If you are reading this at 9:40 at night while a small person who should be asleep negotiates a third glass of water, we see you. Before we hand you a bedtime window, the honest part: every child is different. The figures below are real recommendations from the American Academy of Sleep Medicine, built by a panel of pediatric sleep experts and endorsed by the American Academy of Pediatrics, and they are also exactly what their name says: ranges. A child who sleeps a little outside them and wakes up cheerful, grows well, and gets through the school day is not a problem to fix. Use this page to find a reasonable window, not to grade your child, and not to grade yourself.
How the children's sleep calculator works
In 2016 the American Academy of Sleep Medicine published its consensus recommendations for how much sleep children need at each age, and the American Academy of Pediatrics endorsed them. This calculator embeds that table. Enter your child's age and it identifies the right band, quotes the recommended range, and then does the arithmetic most parents do on their fingers at 9 PM: it counts backward from the wake-up time to find the bedtime window that actually delivers those hours.
One detail matters enough to say twice: for every age under 6, the recommendation is a total per 24 hours including naps. A 2 year old with a two hour afternoon nap does not need 11 to 14 hours at night; the nap is part of the total. So for infants, toddlers, and preschoolers this calculator sets aside a typical nap allocation (about 3 hours, 2 hours, and 1 hour respectively) before computing the nighttime window, and says so in the steps.
| Age | Recommended sleep per 24 hours | Naps included? |
|---|---|---|
| Under 4 months | No recommendation (see below) | No schedule yet |
| 4 to 12 months (infant) | 12 to 16 hours | Yes |
| 1 to 2 years (toddler) | 11 to 14 hours | Yes |
| 3 to 5 years (preschooler) | 10 to 13 hours | Yes |
| 6 to 12 years (school age) | 9 to 12 hours | No |
| 13 to 18 years (teenager) | 8 to 10 hours | No |
And under 4 months? We do not compute anything, on purpose. Newborn sleep is irregular by design: short stretches around the clock while the body clock is still under construction. Healthy newborns vary so widely that the AASM makes no recommendation at all under 4 months, because the evidence will not support one. There is no schedule to enforce yet and nothing to fix; a day and night pattern usually starts to emerge around 3 to 4 months.
The formula
Recommended hours is the AASM range for your child's age band. Nap allocation is the typical daytime portion for napping ages (3 hours for infants, 2 for toddlers, 1 for preschoolers) and zero from age 6 up. The early end of the window uses the top of the range (the most sleep), the late end uses the bottom (the least), and times wrap across midnight automatically.
Worked example
A 7 year old who has to be up at 7:00 AM. School age band (6 to 12 years), so the recommendation is 9 to 12 hours, no naps in the mix.
7:00 AM minus 12 hours = 7:00 PM the evening before. 7:00 AM minus 9 hours = 10:00 PM. The bedtime window is 7:00 PM to 10:00 PM, and most families land near the middle: lights out around 8:00 to 8:30 PM gives 10.5 to 11 hours.
The anchor is the wake time, not the bedtime
Here is the piece of leverage most bedtime battles miss: a consistent wake time does more for a child's sleep than a perfect bedtime. The body clock is set mostly by when the day starts, especially by morning light, so a child who gets up at the same time every day (weekends within about an hour of school days) will start getting sleepy at a predictable hour almost on their own. A meticulously enforced bedtime after wake times that swing two or three hours between Tuesday and Saturday loses to an ordinary bedtime after consistent mornings. Pick the wake time school requires, hold it gently but daily, and let bedtime be the edge that flexes.
Screens, teenagers, and the phase delay that is not laziness
Two honest notes for the older bands. First, screens: the last hour before bed is when a phone does its damage, partly through light and mostly through being more interesting than sleep. Parking devices outside the bedroom for the final 30 to 60 minutes is the single highest-yield sleep habit for school age kids and teens alike, and it works better as a household rule than as a punishment.
Second, teenagers. In adolescence the body clock genuinely shifts later: melatonin release moves back, so a 15 year old told to sleep at 9:30 PM may be biologically unable to comply, lying in the dark wide awake and getting blamed for it. The sleep gap most teens run is created by that shift colliding with early school start times, not by laziness, which is why the AAP formally recommends middle and high schools start no earlier than 8:30 AM. What helps at home: a consistent wake time, morning light, caffeine cut off by early afternoon, and weekend sleep-ins capped at about an hour so Monday does not arrive with jet lag.
When a pediatrician conversation is worth having
This page is educational, and the ranges are population statistics, not a diagnosis of any single child. But a few patterns are worth raising with your pediatrician rather than solving with a spreadsheet: loud snoring most nights, or gasps and pauses in breathing during sleep; regularly taking more than 30 to 45 minutes to fall asleep; heavy daytime sleepiness despite plenty of time in bed, including falling asleep in class or on short car rides past the napping years; and attention or behavior problems that track with poor nights, because insufficient sleep in children can look remarkably like ADHD. None of these mean something is wrong. All of them are better questions for a person who knows your child than for a calculator that does not.