9-Month-Old Milestones and Development
Medically reviewed by Safi Ullah Khan
Medically reviewed by Safi Ullah Khan · Written by Muneeb Rana · Last updated 21 October 2026
Quick answer: 9-month-old milestones: by this age many babies are shy, clingy or fearful around strangers; look when you call their name; and make sounds like 'mamamama' and 'babababa'. These are from the CDC's 9-month checklist (skills 75% of babies show). Every baby develops at their own pace. If your baby loses skills or you're worried, talk to your pediatrician.
TL;DR
- Typical now: is shy, clingy or fearful around strangers; looks when you call their name.
- WHO median weight: 8.9 kg boys, 8.2 kg girls.
- Talk to your pediatrician early about any concern or lost skills.
Here's what 9-month-old milestones usually look like, how growth compares with WHO standards, and simple ways to support your baby this month. Milestones are a guide, not a test: a wide range is normal.
9-month-old milestones checklist
- Is shy, clingy or fearful around strangers
- Looks when you call their name
- Makes sounds like 'mamamama' and 'babababa'
- Lifts arms up to be picked up
- Gets to a sitting position alone
- Sits without support
The CDC 9-month checklist includes being shy or clingy with strangers, showing several facial expressions, reacting when you leave, smiling or laughing at peekaboo, babbling 'mamamama' and 'babababa', looking for objects when dropped, banging two things together and sitting without support.
Growth at 9 months
| WHO standard at 9 months | Boys | Girls |
|---|---|---|
| Median weight | 8.9 kg (19.6 lb) | 8.2 kg (18.1 lb) |
| Typical weight range (3rd-97th percentile) | 7.2-10.9 kg | 6.6-10.4 kg |
| Median length | 72.0 cm (28.3 in) | 70.1 cm (27.6 in) |
WHO growth standards are what the CDC recommends for children under 2. A single number matters less than your baby following their own curve over time. Check a measurement with the growth percentile calculator and see average baby weight by month.
How to support development this month
- Peekaboo and 'where's it gone?'
- Banging and dropping games
- Pointing and naming
You don't need special toys. Talking, reading, floor time and responding to your baby's cues do most of the work.
Feeding and sleep at this age
Feeding: 6-8 oz (180-240 ml) per formula feed, about 3-4 feeds a day; solids: 3 meals plus 1-2 snacks. Sleep: 12-16 hours, with 2 naps. See the 9-month-old feeding chart and 9-month-old sleep schedule.
Checkups and when to act early
The AAP recommends a general developmental screen at the 9-month visit. The CDC encourages parents to act early: if your baby is missing milestones, loses skills they once had, or you have any concern, talk to your pediatrician. Don't wait for the next visit. Tot lets you note milestones and growth so you have dates ready for the appointment.
Related: baby development month by month · 8-month-old development · 10-month-old development · milestone checker · growth chart tracker
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Sources
- CDC: Developmental Milestones (Learn the Signs. Act Early.): www.cdc.gov (accessed 21 October 2026)
- WHO: Weight-for-age standards: www.who.int (accessed 21 October 2026)
- WHO: Length/height-for-age standards: www.who.int (accessed 21 October 2026)
- CDC: WHO Growth Charts for children under 2: www.cdc.gov (accessed 21 October 2026)
- AAP HealthyChildren.org: Corrected Age for Preemies: www.healthychildren.org (accessed 21 October 2026)
Medical disclaimer:
Tot and this website give general information only. Feeding, sleep and growth ranges vary; always follow your pediatrician's advice. If your baby is unwell, contact your doctor or emergency services.
FAQ
What should a 9-month-old be doing?
Many 9-month-olds are shy, clingy or fearful around strangers; look when you call their name; and make sounds like 'mamamama' and 'babababa'. Ranges are wide, and premature babies are usually assessed by corrected age.
Is it OK if my 9-month-old hasn't reached a milestone?
Babies develop at different speeds. Mention it at the next checkup, or sooner if your baby has lost skills or you're worried.
How much should a 9-month-old weigh?
The WHO median at 9 months is 8.9 kg for boys and 8.2 kg for girls, but a wide range is healthy. Following a steady curve matters most.
Should I use corrected age for my preemie?
Yes. The AAP advises using corrected age for development and growth until about age 2 or 3. Use the [corrected age calculator](/tools/corrected-age-calculator).
Can I track milestones in Tot?
Tot focuses on feeds, sleep, diapers, growth, vaccines and medicines. Log weight and height to see growth charts over time. [CONFIRM: milestone logging]
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