Baby timeline
Your baby at 4 months
Rolling, reaching, expressive babble — and often a sleep shake-up around the same time. Once your baby shows signs of rolling, stop wrapping or swaddling for sleep, and keep placing them on their back. The 4-month immunisations and the 4-month Maternal & Child Health visit both fall about now.
What you might notice
4 months
- May roll from tummy to back
- Reaches for and grasps toys
- Babbles with expression
- Shows emotions more clearly
Specialist note: Specialist review if: not holding head steady, no interest in surroundings, or significant developmental concerns.
Typical weights at this age
| Typically around | Most are between | |
|---|---|---|
| Girls | 6.4 kg | 5.1–8.1 kg |
| Boys | 7 kg | 5.6–8.6 kg |
Ranges are the WHO Child Growth Standards typical range (3rd–97th centile) at this age. Babies born early are tracked by corrected age. Weights vary — your MCH nurse tracks your baby’s own curve, which matters more than any single number.
Trusted resources
Your baby’s own timeline
Enter a birth date on the timeline tool to see milestones tuned to your baby — including corrected age for babies born early — and take the whole first 18 months with you as calendar reminders.
Open the baby timelineGeneral information only, aligned with Raising Children Network and green book developmental guidance. Babies vary, and corrected age applies for babies born early.
Concerns about your baby? Start with your MCH nurse (MCH Line 13 22 29) or your GP. For 24-hour nurse advice: NURSE-ON-CALL 1300 60 60 24.
In an emergency call 000. Last reviewed 2026-08-25.