Baby Sleep Calculator

Sleep needs shrink steadily through the early years. Widely used pediatric guidance puts newborns (0–3 months) at 14–17 hours per 24 hours, babies 4–12 months at 12–16 hours, toddlers 1–2 years at 11–14 hours, and preschoolers 3–5 years at 10–13 hours — naps included. Your baby is an individual, so treat these ranges as a starting point and watch how they behave.

Bedtime is anchored to the morning

The cleanest way to pick a bedtime is to work backward from morning wake time. If your baby needs about 11 hours of night sleep and you want them up at 7 AM, bedtime lands at 8 PM. This keeps the whole 24-hour cycle stable even when individual nap lengths vary from day to day.

Keep the range in mind

• Too-early bedtime isn't usually a problem if naps ran long — but if bedtime battles stretch past 30 minutes, the nap day may have been too generous.
• Too-late bedtime tends to shrink total night sleep, because most babies still wake around the same morning time.
• Consistency beats precision: a bedtime within the same 30-minute window each night supports the body's sleep cues more than any single "perfect" time.

When your baby moves through a nap transition — dropping from 3 naps to 2, or 2 to 1 — bedtime often needs to shift earlier for a week or two while the longer wake windows settle in. That's normal and temporary.

Growth spurts, teeth, and illness move the goalposts

Some weeks your baby will sleep noticeably more than the ranges above, and that's expected. Growth spurts, developmental leaps, and recovery from illness all raise sleep need temporarily — a baby who usually takes 11.5 hours at night may want 12.5 for a few days. Follow their cues and let bedtime creep earlier rather than fighting to hold the clock time.

The opposite is also true: around 4, 8, 12, and 18 months, sleep regressions commonly bring 1–2 weeks of shorter nights and harder naps. During a regression, don't redesign the schedule — hold the same wake time and bedtime window, and protect daytime sleep, because a well-rested baby navigates a regression much faster than an overtired one. If short nights persist beyond two or three weeks, or your baby seems unwell, it's worth mentioning to your pediatrician.

A note on night wakings

Some night waking is developmentally normal well into the second year — babies cycle between light and deep sleep and often briefly stir. The bedtime range this calculator gives you already assumes a realistic night, not a fantasy one. What matters is the total: if your baby wakes twice but returns to sleep quickly and wakes happy at the target time, the schedule is working. Only when total night sleep consistently lands below the range is it a sign bedtime needs adjusting.