11 hfrom bedtime to morning wake-up at 3 months, and still about 11 h at 18 months. Naps do most of the shrinking.
Total sleep falls from 14.7 to 12.4 hours a day between 3 and 18 months, and most of the drop is daytime sleep: naps go from 3.7 to 1.7 hours. The night here is the whole stretch from bedtime to morning wake-up, so it includes any time awake in it.
Total sleep by age
For the middle baby, total sleep falls from about 14 h 40 min a day at 3 months to about 12 h 25 min at 18 months, and naps account for about 2 hours of that drop.
- Night, bedtime to morning wake-up
- Naps
The line is a typical baby. Most babies fall somewhere in the shading, so being above or below the line is normal.
Each column is the middle baby's night, from bedtime to morning wake-up, with the middle baby's naps on top. The night includes any time awake in it. The bands behind the columns show total sleep for half of babies (the inner band) and 9 in 10 babies (the wider band). Naps go from 25% of all sleep at 3 months to 14% at 18 months, so sleep is moving into the night.
Complete days only: a day counts when a parent logged the morning wake-up, every nap and bedtime, with at least one nap. The night is the time from bedtime to the next morning wake-up. Each baby counts once per month of age, as its own average over at least 7 complete days, so every baby gets one vote. Unsettled weeks count too: nothing is left out for being irregular. Only what parents entered is used. Source: Napper analytics, aggregated, ~403,000 babies · 47 million baby-days, Oct 2025 to Sep 2026.