Baby age, week by week
16 Weeks Old — How Many Months?
A 16-week-old baby is 112 days old — about 3 months and 21 days.
This week
The famous four-month sleep bump can start, and some babies roll front to back.
The math
16 weeks = 112 days ≈ 3 months + 21 days
A month is longer than 4 weeks — on average 30.44 days — so you can't just divide by 4. The exact answer shifts a little with the calendar, so for the day-perfect number, use the calculator with your baby's real birthday.
Get the exact age →What babies do around week 16
At 16 weeks your baby is near the 4 Months mark. Around this age, many babies:
- Rolls from tummy to back like a pro
- Sees farther and picks out colors better now
- Smiles and laughs more, all on their own