The second half of the first year is when most babies become mobile and start communicating on purpose. Over these months they usually go from sitting with support to sitting alone, then find a way to move (crawling, commando crawling or bottom shuffling), pull up to stand and cruise along furniture. Their hands go from raking food towards them to a neat thumb-and-finger pick-up, and their sounds go from squeals and raspberries to "mamama" and, by around a year, a special name for you.
The CDC's checkpoints at 6 months, 9 months and 12 months list skills that 75% or more of babies can do by each age. That makes them a sensible "by now" marker rather than an average, so if something is missing it's worth raising rather than waiting to see.
What are the milestones at 6, 9 and 12 months?
By 6 months
| Area | What most babies do by 6 months |
|---|---|
| Social and emotional | Know familiar people; like looking at themselves in a mirror; laugh |
| Language | Take turns making sounds with you; blow raspberries; squeal |
| Thinking and learning | Put things in their mouth to explore; reach to grab a toy they want; close lips to show they don't want more food |
| Movement | Roll from tummy to back; push up with straight arms on their tummy; lean on their hands to support themselves when sitting |
Pregnancy, Birth and Baby's 6-month page adds that many babies sit with support, take some weight on their legs when held standing and pass toys from hand to hand. Our 4–6 month milestones guide covers the months leading up to this point, and rolling over explains how that skill develops.
By 9 months
| Area | What most babies do by 9 months |
|---|---|
| Social and emotional | Are shy, clingy or fearful with strangers; show several facial expressions; look when you call their name; react when you leave; smile or laugh at peek-a-boo |
| Language | Make lots of different sounds like "mamamama" and "bababababa"; lift arms up to be picked up |
| Thinking and learning | Look for things dropped out of sight; bang two things together |
| Movement | Get to a sitting position alone; sit without support; move things from one hand to the other; rake food towards themselves with their fingers |
The 9-month visit is also when the CDC's developmental screening page says the AAP recommends a standardised developmental screen for every child, along with screens at 18 and 30 months. Ask about it at your baby's check if it isn't offered.
By 12 months
| Area | What most babies do by 12 months |
|---|---|
| Social and emotional | Play games with you, like pat-a-cake |
| Language | Wave bye-bye; call a parent "mama", "dada" or another special name; understand "no" (pause or stop when you say it) |
| Thinking and learning | Put something in a container, like a block in a cup; look for things they saw you hide |
| Movement | Pull up to stand; walk holding on to furniture; drink from an open cup you hold; pick things up between thumb and pointer finger |
Independent walking is not on the CDC's 12-month list. Pregnancy, Birth and Baby's 12-month page says babies this age may walk holding a hand or stand alone for a moment. See first steps for the walking timeline.
When do babies sit, crawl, stand and walk?
The World Health Organization followed healthy babies in Ghana, India, Norway, Oman and the USA and recorded when they first reached six movement milestones. The WHO motor development study describes these "windows of achievement" as normal variation among healthy children.
| Skill | Normal window (months) | Half of babies by |
|---|---|---|
| Sitting without support | 3.8 to 9.2 | 5.9 months |
| Standing with help | 4.8 to 11.4 | 7.4 months |
| Crawling on hands and knees | 5.2 to 13.5 | 8.3 months |
| Walking with help | 5.9 to 13.7 | 9.0 months |
| Standing alone | 6.9 to 16.9 | 10.8 months |
| Walking alone | 8.2 to 17.6 | 12.0 months |
Each window runs from the age the earliest 1% of babies reached the skill to the age 99% had. In the study, 4.3% of babies were never seen crawling on hands and knees, and the authors note that some babies move another way instead, such as bottom shuffling or crawling on their stomach.
The AAP's 8–12 month movement guide says crawling is usually mastered between 7 and 10 months and many first steps come around the first birthday. Our guides to sitting up and crawling go into each skill.
How do hands, sounds and understanding change from 6 to 12 months?
- Hands. At 6 months babies reach and grab. By 9 months they pass toys between hands and rake food with their fingers. By 12 months most pick up small bits of food between thumb and pointer finger and can drop a block into a cup on purpose.
- Sounds and words. Squeals and raspberries at 6 months become repeated babble ("bababa") by 9 months. By 12 months most babies have a name for a parent and understand "no". Our first words guide covers the path to talking.
- Understanding. Around 9 months babies look for a spoon or toy dropped out of sight. By 12 months they search for things they watched you hide.
- Feelings. Wariness of strangers and upset when you leave are on the CDC's 9-month list. Pregnancy, Birth and Baby's 9-month page notes many babies show separation anxiety at this age. See separation anxiety.
How can I help my baby learn through play from 6 to 12 months?
These ideas come from the CDC's 6-, 9- and 12-month tips and Pregnancy, Birth and Baby:
- Keep up the back-and-forth. Copy your baby's sounds, then add a real word: if they say "ba", say "ba-ba-ball".
- Name what they look at. When your baby looks or points at something, point too and talk about it ("a big red truck").
- Put toys just out of reach on the floor or play mat so your baby rolls, scoots or crawls to get them, and celebrate when they do.
- Play peek-a-boo and hiding games. Cover a toy with a cloth and let your baby find it.
- Take turns. Pass a toy back and forth, or fill and tip out a container of blocks together.
- Teach gestures. Wave bye-bye and shake your head for "no"; gestures help babies communicate before words.
- Give safe things to pull up on and push. Sturdy furniture, a stable push toy or an empty box all help with standing and early walking.
- Read every day. Talking about pictures counts as reading at this age.
The CDC recommends keeping screens to video calls with loved ones before age 2.
How do I keep a baby on the move safe?
Pregnancy, Birth and Baby notes that many babies can roll by 6 months, so never leave your baby alone on a change table or bed. The AAP warns that nappy changes on a change table become risky once your baby can flip over, and suggests changing them lower down, such as on the floor.
- Fit sturdy gates at the top and bottom of stairs and keep them closed (AAP).
- Keep electrical cords, unstable furniture and hot drinks well out of reach (Pregnancy, Birth and Baby).
- Lock away medicines, chemicals and cleaning products (CDC).
- Scan the floor for small objects. Pregnancy, Birth and Baby's choking guide says anything smaller than a 20-cent coin can choke a child under 3 years.
- Skip baby walkers. The AAP strongly urges parents not to use them.
Our choking vs gagging guide explains the difference at mealtimes.
What if my baby was born early or does things in a different order?
If your baby was born more than 3 weeks early, the CDC's online checklist says to use their corrected age, counted from their due date. If their age falls between two checklists, use the younger one.
Babies don't all follow the same route. Some sit early and crawl late; some never crawl. A baby who is steadily gaining skills, uses both sides of their body and arms and legs equally, and is interested in people and toys is usually on their own healthy track. The AAP says to discuss it with your paediatrician if your baby doesn't seem to be moving normally.
When should I talk to a GP or child-health nurse?
Call your local emergency number (000 in Australia, 999 in the UK, 911 in the US) now if your baby
- has difficulty breathing, is breathing very fast, or is grunting or sucking in at the ribs or tummy
- has blue, grey, pale or blotchy skin, lips or tongue
- is very drowsy, hard to wake, floppy or not responding like they normally do
- is having a seizure (fit)
These come from the NHS urgent help guide and healthdirect.
See a doctor promptly if your baby
- has stopped doing something they could do before, such as babbling, sitting or responding to you
- seems unusually stiff or floppy, or uses one side of the body much more than the other
Raise it soon with your GP or child-health nurse if
| By about (corrected age) | Worth raising if your baby |
|---|---|
| 6 months | Isn't trying to roll, isn't making sounds, doesn't respond to familiar faces, or isn't holding objects |
| 9 months | Isn't sitting without support, isn't babbling, isn't responding to carers or making eye contact |
| 12 months | Shows no attempts to move (crawling, shuffling or pulling to stand), isn't babbling, isn't passing toys between hands or isn't interested in toys |
These signs are drawn from Pregnancy, Birth and Baby's 6-, 9- and 12-month pages and the AAP. Missing any item on a CDC checklist is also worth mentioning. The CDC's advice is not to wait: share your concerns and ask about developmental screening.
What's worth writing down?
Note the date you first see a new skill and how your baby moves around (crawling, shuffling, rolling). If you're unsure whether something is typical, write down what you saw and when, and take the notes to your next check. A short video on your phone can also help a GP or child-health nurse see what you mean.
