Average weight at 9 monthsGirls 8.2 kg (18.1 lb)
Boys 8.9 kg (19.6 lb)
Boys 8.9 kg (19.6 lb)
Average length at 9 monthsGirls 70.1 cm (27.6 in)
Boys 72.0 cm (28.3 in)
Boys 72.0 cm (28.3 in)
50th percentile (median) on the WHO Child Growth Standards. Healthy babies vary widely around these numbers.
Development at 9 months
Your baby is becoming a little explorer, sitting steadily, moving around and showing clear feelings about the people around them.
CDC milestones most babies reach by 9 months
- Is shy, clingy or fearful around strangers
- Shows several facial expressions, such as happy, sad, angry and surprised
- Looks when you call their name
- Reacts when you leave
- Smiles or laughs when you play peekaboo
- Makes lots of different sounds like mamamama and babababa
- Lifts arms up to be picked up
- Looks for objects when dropped out of sight
- Bangs two things together
- Gets into a sitting position by themselves
- Moves things from one hand to the other
- Uses fingers to rake food towards themselves
- Sits without support
Feeding
Most babies eat three small meals plus one or two snacks, alongside breast milk or formula. Offer soft finger foods and let your baby practise with an open cup.
Sleep
Most babies need 12 to 16 hours of sleep in 24 hours, with 2 naps. Put your baby down on their back on a firm, flat surface with nothing loose in the cot.
Your checklist this month
- Book the 9-month check-up. The AAP recommends a developmental screening at this visit.
- Move cot mattresses to a lower level if your baby can pull up.
- Keep cleaning products and medicines locked away.
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.