Enter your child’s age and the time they have to be up, and this calculator works backwards to a lights-out window that fits inside the sleep range recommended for that age group by the American Academy of Sleep Medicine.

Recommended sleep by age

These are the consensus ranges from the American Academy of Sleep Medicine, and they count all sleep in 24 hours, naps included — which is why the calculator subtracts naps before setting the overnight window.

Newborns under four months are deliberately not in the table: their sleep is not yet consolidated and no bedtime schedule applies. Follow your pediatrician’s guidance there.

Making the bedtime actually work

• Same time every night, including weekends. Drifting more than an hour on weekends produces a Monday morning that looks exactly like jet lag.
• Wind down for 30 to 45 minutes. Bath, pyjamas, two books, lights low, same order every night. The predictability is what does the work.
• Screens out of the bedroom. Late screen light delays sleep onset and the content itself keeps kids alert — for teenagers this is usually the single biggest lever.
• Cool and dark. A bedroom in the mid-60s Fahrenheit with blackout curtains beats any bedtime trick.
• Teens are biologically late. Adolescent body clocks shift later, so an 8:30pm bedtime is not realistic at 15. Protect the wake time, fight for the 8-to-10-hour window, and use morning daylight.

FAQ

My child’s bedtime lands earlier than they will accept. What now?

Move in 15-minute steps every few nights rather than an hour at once, and shift the wake-up time earlier at the same rate so sleep pressure builds. Sudden large shifts turn bedtime into a negotiation and usually fail.

When should a nap be dropped?

Most children stop napping between three and five years old. The practical signal is that the nap has started pushing bedtime late or causing long lights-out struggles. Cap it, move it earlier, then drop it, and shift bedtime earlier to keep the 24-hour total inside the range.

Does a kid’s mattress affect sleep quality?

Yes, though less dramatically than for adults. What matters most is a firm, well-supported, properly sized surface with breathable bedding and a cool room. Growing kids sleep hot, and over-soft or worn surfaces cause the tossing and repeated night waking parents usually blame on behaviour.

Are these times a medical recommendation?

No. The ranges come from the AASM consensus, but the calculator output is a starting schedule, not clinical advice. Loud snoring, pauses in breathing, night terrors, persistent bedtime resistance or daytime sleepiness should be raised with your pediatrician.

Should teenagers use the adult sleep calculator instead?

For cycle timing yes, as long as they target 8 to 10 hours rather than the 7 to 9 an adult needs. This page is the faster route because it enforces the teen range automatically.

If the room and the bed are the problem

When the routine is solid and a child still wakes repeatedly, look at temperature, light and the sleep surface before anything else. A worn, too-soft or too-hot mattress is a common and easily fixed cause.

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