Boys 7.0 kg (15.4 lb)
Boys 63.9 cm (25.2 in)
50th percentile (median) on the WHO Child Growth Standards. Healthy babies vary widely around these numbers.
Development at 4 months
Your baby is laughing, reaching for toys and may start rolling from tummy to back. They are curious about everything and love interaction.
CDC milestones most babies reach by 4 months
- Smiles on their own to get your attention
- Chuckles when you try to make them laugh
- Makes sounds like oooo and aahh
- Makes sounds back when you talk to them
- Turns head towards the sound of your voice
- Opens mouth when they see a breast or bottle if hungry
- Looks at their hands with interest
- Holds head steady without support when you hold them
- Holds a toy when you put it in their hand
- Uses arm to swing at toys
- Brings hands to mouth
- Pushes up onto elbows or forearms on tummy
Feeding
Breast milk or formula is still all your baby needs. The AAP recommends waiting until about 6 months to start solid foods, and not starting before 4 months.
Breast milk or formula is all your baby needs until around 6 months. Feed when your baby shows hunger cues, such as rooting, sucking on hands or turning towards the breast. Breastfed babies usually need a vitamin D supplement: the AAP recommends 400 IU a day. Work out formula amounts with our Baby Feeding Calculator.
Sleep
Some babies go through a phase of more night waking around 4 months as their sleep patterns mature. Babies this age usually need 12 to 16 hours of sleep in 24 hours, including naps. Always put your baby down on their back, on a firm, flat surface with no pillows, bumpers or loose blankets. The AAP recommends sharing your room, but not your bed, for at least the first 6 months.
Your checklist this month
- Book the 4-month check-up and vaccinations.
- Never leave your baby alone on a raised surface: rolling can start any time.
- Learn the signs of readiness for solids.
Is your baby growing well?
Check weight, length and head size on WHO charts with our Baby Growth Percentile Calculator, or work out your baby’s exact age with the Baby Age Calculator.