4-Month Milestones
What many babies do by 4 months and how caregivers can support development
At four months, many babies are becoming more interactive, exploring with their eyes and hands, and using their voices to communicate joy and curiosity. This page breaks down typical milestone expectations, offers real-life examples, and suggests ways caregivers can encourage growth through everyday play.
Note: These milestone descriptions reflect what most babies (about 75% or more) are expected to demonstrate by 4 months of age.
Social & Emotional Milestones
By four months, many babies:
Smile on their own to get your attention; a social “hello.”
Chuckle (not yet a full laugh) when you try to make them laugh; early joyful engagement.
Look at you, move, or make sounds to get or keep your attention; showing early intentional social behavior.
Everyday context:
When you make a funny face, and your baby responds with a lively smile or a little chuckle, they’re practicing social connection and learning how their actions influence your reactions.
Language & Communication Milestones
At this age, many babies:
Make sounds like “oooo,” “aahh” (cooing); those are early speech-like sounds.
Make sounds back when you talk to them; an early conversational exchange.
Turn their head toward the sound of your voice, showing interest in communication.
Real-life example:
When you speak to your baby and pause, and they “respond,” that back-and-forth is the earliest form of conversation and lays the foundation for expressive language later.
Cognitive (Thinking & Learning) Milestones
Many four-month-olds:
Open their mouth when hungry if they see the breast or bottle; a sign of early expectation and memory.
Look at their hands with interest; an early sign of self-exploration and curiosity.
What this means:
Exploring hands or briefly watching objects demonstrates growing attention and curiosity, which are key building blocks of problem-solving and learning.
Movement & Physical Development Milestones
By four months, many babies:
Hold their head steady without support when held, as strengthened muscles result in better neck and trunk control.
Hold a toy when placed in their hand; they are beginning to use their hands purposefully.
Use their arm to swing at toys, practicing reach and coordination.
Bring hands to mouth, an important early self-exploration behavior.
Push up onto elbows/forearms during tummy time, building strength for rolling and later sitting.
Everyday examples:
During play mat time, a baby pushing up on forearms shows strengthening muscles that support future postures like sitting.
Reaching for and holding a soft toy shows growing coordination and intention.
How You Can Support Your Baby’s Development
At four months, babies learn through active interaction, movement, and repetition. They are becoming more aware of their bodies, more interested in people and objects, and more intentional in how they communicate. Development is supported when caregivers create opportunities for exploration within familiar, responsive routines. These activities don’t require special equipment or schedules. When repeated through everyday interactions, they create the conditions where new skills can emerge naturally.
You can support your baby’s development by:
Smiling, talking, and responding when your baby makes sounds. When you react with positive vocal and facial feedback, it encourages early communication and social interaction.
Providing safe opportunities for your baby to reach for and kick at toys. Letting your baby explore objects helps build early coordination and curiosity.
Allowing your baby to safely explore objects with their mouth. Babies learn a lot by seeing, touching, and mouthing safe items.
Talking, reading, and singing throughout the day. Repeated language exposure supports early listening and later speaking skills.
Giving your baby safe toys that are easy to hold. Simple, age-appropriate toys give your baby something to explore and practice intentional movement.
Letting your baby move and interact with people and objects throughout the day. Daily exploration and contact help babies learn about movement and connection.
Setting predictable routines for feeding and sleep. Consistent patterns help babies anticipate what comes next, supporting learning and regulation.
Showing a bright-colored toy while your baby lies on their back and moving the toy slowly side to side or up and down. This encourages visual tracking and attention.
Using music or voice while gently moving your baby’s arms and legs. This supports early movement experience and body awareness.
Playing simple games like peek-a-boo or bouncing with feet on your lap. These activities reinforce interaction, timing, and physical fun.
Copying your baby’s sounds and engaging in back-and-forth “talking.” This helps babies learn the rhythm of communication.
Calling your baby by name as you interact. Hearing their name repeatedly helps them begin to recognize it.
Playing on the floor or a play mat daily. Regular time on the floor supports movement exploration and variation.
Holding, talking to, and smiling with your baby during play and quiet moments. These shared moments build connection and engagement.
Having quiet play times when you sing or “read” to your baby. This supports attention and early language exposure.
These interactions help babies practice coordination, communication, and curiosity, which are the foundations for future skills.
Printable Tools & Next Steps
Download or view a checklist you can use during everyday routines to track which milestones your baby is demonstrating.
Bring your checklist to well-child visits and use it to support conversations with your pediatric healthcare provider.
Test Your Knowledge
A quick check, or a fast refresher if you’re short on time
1. Social-Emotional - Your baby looks at you and moves to get your attention. What does this show?
A. They’re practicing early social communication
B. They’re bored
C. They want to sleep
-
A. They’re practicing early social communication
2. Language – When your baby coos back at you during play, what does it signal?
A. They’re hungry
B. They’re practicing early conversation skills
C. They want quiet time
-
B. They’re practicing early conversation skills
3. Cognitive – Your baby brings their hands to their mouth and looks at them. This is important because:
A. It keeps them busy
B. It means they’re tired
C. It supports early exploration and learning
-
C. It supports early exploration and learning
4. Movement – Your baby pushes up onto their elbows during tummy time. Why is this helpful?
A. It gets them off the floor
B. It strengthens muscles for future skills like rolling and sitting
C. It means they’ll walk early
-
B. It strengthens muscles for future skills like rolling and sitting
Please note that…
This information is intended to support learning and awareness, not to replace guidance from a healthcare or early childhood professional.