Your 4-Month-Old Baby’s Development and Milestones

At 4 months old, your baby is entering an exciting stage of development marked by increased social interaction, improved motor skills, and a growing curiosity about the world. If you’re wondering what a 4-month-old should be doing, here are some common milestones:

• Motor Skills. Holds head up, pushes up on elbows, brings hands to mouth, and may start to roll over.

• Cognitive and Sensory. Watches faces, explores hands, tracks moving objects, and starts recognizing familiar people.

• Communication. Coos, babbles (like "ahh" or "ba"), and turns toward voices.

• Feeding. Eats about 24–36 ounces of breast milk or formula per day.

• Diapering. Has several wet diapers daily and regular soft bowel movements.

• Sleep. Sleeps 12–16 hours a day, including nighttime stretches and 3–4 hours of daytime sleep.

• Health. Time for the 4-month check-up and vaccines like DTaP, Hib, Polio, Pneumococcal, and Rotavirus.

Every baby develops at their own pace, but understanding what’s typical at 4 months can help you feel more confident and know when to check in with your healthcare provider. In this guide, we’ll walk through each of these areas in more detail and offer tips for supporting your baby’s growth and routines.

Baby Development Milestones

Now that your little one is 4 months old, daily life may feel a bit more predictable as routines begin to settle. Still, your baby is likely keeping you on your toes—and that’s completely normal.

At this age, your child is actively developing their motor skills . You may notice them trying to grasp objects, push up with more control during tummy time, or even start to roll over. Some babies can sit up briefly with support or bear a bit of weight when held upright. These early movements lay the foundation for future coordination and strength.

Want to keep track of your baby’s development this month? Download the free monthly milestone printable to celebrate the progress you're seeing, one adorable moment at a time.

Average Weight and Height of a 4-Month-Old

By 4 months, many babies have doubled their birth weight. This month, your baby may gain about 1 to 1¼ pounds in weight and grow almost an inch in length. But it’s also okay if your little one grows a little more or a little less.

So, how much should a 4-month-old weigh? According to the World Health Organization (WHO) growth standards, which the CDC recommends, the average weight of a 4-month-old baby at the 50th percentile is about 15. 4 pounds (7. 0 kg) for boys and 14. 1 pounds (6. 4 kg) for girls. The average length for a 4-month-old is 25. 2 inches (63. 9 cm) for boys and 24. 4 inches (62. 1 cm) for girls.

If you're wondering where your little one falls on the average of the 4-month-old weight percentile chart, your baby’s healthcare provider can help interpret these numbers during regular checkups.

The focus is on long-term trends, rather than achieving a single target. Also, don't be surprised if you notice signs of a 4-month growth spurt, such as increased appetite, fussiness, or brief sleep disruptions—these are completely normal and usually pass within a few days. Growth spurts are a natural part of development as your little one’s bones, muscles, and fat stores continue forming. They’re influenced mainly by genetics, but things like diet, environmental factors, and pregnancy health can also play a role in how and when your baby grows.

To get a clearer picture of your baby's growth pattern, your provider will likely use baby growth charts to monitor changes in both weight and length over time. Use our Growth Chart Calculator to get a better idea of how your little one’s size compares to averages.

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Cognitive Development

Your little one’s world is coming into focus. Your 4-month-old’s eyesight is improving steadily, with sharper detail and better colour perception. Many babies this age can recognize familiar faces across the room and easily track slow-moving objects with their eyes.

By 4 months, your baby is becoming more aware of the world and how they interact with it. You might notice them watching your face, responding to your voice, or smiling back when you smile—early signs of social and cognitive growth.

So, how far can a 4-month-old see? By now, their visual range may have increased to several feet—or even more—allowing them to follow movement across a room or notice you from a distance. Their 4-month-old vision also includes improved depth perception and the ability to notice contrast and brighter colours. You may notice that your baby is particularly drawn to vibrant hues like red and blue.

Another source of endless visual fascination for your 4-month-old baby? Themselves! An unbreakable mirror is an excellent toy for infants of this age, as they can see a wide range of colours and shapes, as well as their own movements in their reflection.

Language skills are also beginning to emerge. Your baby may start to mimic the tone of your voice, and their cries might sound different depending on what they need. These early coos and babbles are the foundation for future speech.

Wondering when actual words might come? Learn more about when babies start talking.

Physical Development: Gross and Fine Motor Skills

Your baby’s movements are becoming more deliberate as they begin to explore the world in new ways. Around this age, you might notice the development of key motor skills for a 4-month-old, such as reaching for toys, bringing their hands to their mouth, or holding onto objects with increasing control. These early ">fine motor skills , often developed by 4-month-olds, often go hand-in-hand with improved vision and a growing interest in everything around them.

Physically, your little one is also gaining strength. These early 4-month gross motor milestones might include lifting their chest during tummy time, holding their head up independently , and even beginning to roll over from one side to the other.

Here’s a quick look at what motor skills a 4-month-old should have or be working toward:

• Holding their head up

• Bringing hands to mouth

• Sitting with support

• Reaching for and grasping toys

• Pushing up during tummy time

• Starting to roll over.

Every baby develops at their own pace, so don’t worry if your little one isn’t doing all of this just yet. Their healthcare provider will keep an eye on progress during checkups.

4-Month-Old Behaviour Changes

At this stage, 4-month-old behaviour changes may become more noticeable as your baby grows more aware of their surroundings. They may react to your tone of voice—calm tones can soothe them, while louder or sharper tones might signal distress. You may also hear your little one trying to mimic your voice through coos and babbles.

Babies under one year often express growth spurts through fussiness and periods of increased hunger. These moments can be challenging, so it helps to be patient and offer comfort as your baby adjusts to their rapidly developing body and brain.

Some babies are naturally more curious or expressive, while others may seem shy or more sensitive. If your baby appears overstimulated or quiet in new situations, that’s completely normal. Gently support them with extra cuddles and time to adjust.

Teething

Can a 4-month-old be teething? Yes—it’s early, but not uncommon. While most babies start teething around 6 months, some begin showing signs as early as 4 months old.

Drooling, chewing on hands, and fussiness may all be early clues. To soothe their teething , a chilled teething ring or a clean finger gently rubbed on the gums can offer relief. If you’re unsure whether it’s teething or something else, check with your little one’s healthcare provider.

4 Month Growth Spurt

Don't be surprised if you notice signs of a 4-month growth spurt, such as increased appetite, fussiness, or brief sleep disruptions—these are completely normal and usually pass within a few days. Growth spurts are a natural part of development as your little one’s bones, muscles, and fat stores continue forming. They’re largely influenced by genetics, but things like diet, environmental factors, and pregnancy health can also play a role in how and when your baby grows.

How Much and How Often Should a 4-Month-Old Eat?

Your 4-month-old is growing fast, and all of their nutrition still comes from breast milk, formula , or both.If you’re wondering when it’s time to feed, just keep an eye out for common hunger cues like:

• Licking their lips

• Sucking on hands or knuckles

• Sticking out their tongue

• Acting fussy or restless.

So, how much should a 4-month-old eat? Most babies take about 4 to 6 ounces of breast milk or formula per feeding, usually every 3 to 5 hours. This typically adds up to around five to seven feedings a day, though your little one might need more or less depending on the day.

Tracking how many ounces a 4-month-old should eat daily? A general range is 24 to 36 ounces per day, though this can vary. As long as your baby is gaining weight, producing wet diapers, and seems content after feeding, they’re likely getting what they need.

Want help building a feeding rhythm? Explore our baby feeding schedule to get a better sense of what a typical day might look like.

Activities for a 4-Month-Old

Looking for ideas on what to do with a 4-month-old? At this stage, your baby is becoming more aware, social, and curious, which makes it a great time to explore simple ways to play, connect, and support their development. Whether you’re building routines or seeking fresh inspiration, here are some engaging daily activities for a 4-month-old that also promote growth.

• To encourage visual development:

  • Hang a colourful mobile safely above the crib.

  • Let them marvel at their reflection in a mirror.

  • Play peekaboo to introduce object permanence —they love watching your face reappear!

• To build muscle strength and motor control:

  • For a 4-month-old, tummy time may be daily. Wondering how much tummy time at 4 months? Aim for 2 to 3 times per day for a short 3 to 5 minutes.

  • Support them in a seated position so they can reach and explore.

  • Practice standing by gently pulling them up while holding them under their arms.

• To support language development:

  • Talk, sing, and read throughout the day.

  • Mimic your baby’s sounds—and respond when they mimic yours.

• Other simple activities for a 4-month-old can include:

  • Showing them safe household objects, such as a wooden spoon or plush toy, to grab, which supports fine motor skills.

  • Gently swaying or dancing while holding your baby.

• Letting them meet other babies and parents—just watch for signs that they may be overstimulated.

Curious about how to entertain a 4-month-old? Often, just being responsive and in sync with their mood offers the most valuable stimulation. These early interactions help your little one feel secure and strengthen your bond.

Tummy Time

For a 4-month-old, tummy time is an important activity. Wondering how much tummy time at 4 months? Aim for 2 to 3 times per day for a short 3 to 5 minutes. This helps build muscle strength and motor control.

Diapering and Pooping at 4 Months Old

By now, you’ve likely started noticing patterns in your little one’s diaper routine, but things can still vary day to day. So, how often should a 4-month-old poop? At 4 months, a baby should have several wet diapers a day and regular bowel movements, as long as the poop is soft. If it becomes hard, dry, or difficult to pass, let your healthcare provider know.

To help keep your baby dry and comfortable through all those changes, Pampers Swaddlers offer soft materials and up to 12 hours of leak protection, day or night.

How Much Sleep Does a 4-Month-Old Need?

Sleep at this age is starting to shift as your baby becomes more alert during the day. If you’re wondering how much sleep a 4-month-old should get, most babies this age sleep between 12 and 16 hours within 24 hours.

This often includes 3 to 4 hours of daytime sleep, split into two naps—usually one in the morning and one in the afternoon—so if you’re tracking how much daytime sleep for a 4-month-old, that’s a helpful range to aim for. At night, it may vary, but many babies sleep about 6 to 8 hours (sometimes with brief wakings for feeding or comfort).

A consistent evening routine may help ease bedtime transitions, especially now that your little one is more aware of their surroundings. Warm baths, gentle massage, soft music, feeding, or rocking may all be soothing ways to wind down. Around this stage, your little one might also go through the 4-month sleep regression —a normal, temporary phase where sleep becomes lighter and more disrupted due to brain and body development.

If sleep has suddenly become more challenging, you're not alone. This phase can make parents start thinking about long-term sleep habits . As your baby nears 5 months, you may begin considering sleep training—a gradual approach that helps babies learn to fall asleep on their own and stay asleep longer. Not sure where to start? The Smart Sleep Coach app offers a personalized plan, sleep tracking, and calming meditations—and you can begin by taking a free sleep readiness assessment.

4 Month Check-Up and Vaccination

At your baby’s 4-month check-up, their healthcare provider will check growth, review developmental milestones, and answer any questions you have about feeding, sleep, or behaviour.

Your child will get most of their immunizations by their second birthday , and a good portion of these happen in the first year. Because infants are vulnerable to serious illnesses, following the recommended vaccine schedule from birth to 12 months is an important step in protecting your baby. This visit may also include the next round of 4-month vaccines. These 4-month-old immunizations help protect your little one from several serious illnesses.

• Rotavirus (dose 2)

• DTaP (diphtheria, tetanus, pertussis – dose 2)

• Hib (Haemophilus influenzae type b – dose 2)

• PCV (pneumococcal conjugate – dose 2)

• IPV (inactivated poliovirus – dose 2).

These 4-month check-up vaccinations are part of the recommended immunization schedule and help keep your baby protected as they grow.

Your Baby’s Health

At 4 months, your baby may seem more alert and active, but it’s also a time when many parents start navigating minor illnesses or developmental health checks.Whether your baby is dealing with a stuffy nose or heading in for a 4-month checkup, here’s what to know:

• Fever. A fever in a baby is usually a sign that their body is fighting an infection. In infants, a rectal temperature of 100. 4°F or higher is considered a fever. This could be linked to a cold, flu, ear infection, or something more serious like pneumonia. To take your baby’s temperature accurately, use a digital thermometer inserted rectally, with no more than ½ to 1 inch of insertion. If your baby has a fever, it’s best to contact your healthcare provider, especially if other symptoms are present.

• Colds and common illnesses. Colds are very common in infants and are caused by viruses. Your little one may experience a runny nose, sneezing, mild fever, or reduced appetite.Though colds usually pass on their own, call your baby’s healthcare provider if you notice:

  • A persistent cough lasting more than a week

  • Bluish lips or fingertips

  • High fever (over 102°F)

  • Unusual sleepiness or fussiness.

• Bronchiolitis. Bronchiolitis is a viral infection common in babies, especially in colder months. It affects the small airways in the lungs and is very contagious. Be extra mindful of handwashing and hygiene.Contact your baby’s healthcare provider if they:

  • Wheeze when breathing

  • Struggle to drink fluids

  • Have bluish lips or fingertips

  • Show signs of dehydration (fewer wet diapers, dry mouth, or lethargy).

Items You Will Need This Month

• Schedule and attend your baby’s 4-month checkup and ask about any upcoming vaccines. You can review the full immunization schedule here .

• Before the visit, jot down any questions you have about feeding, sleep, growth, or behaviours. Be sure to mention any recent symptoms like fever, vomiting, rashes, or developmental concerns.

• Curious about what’s ahead? Check out this guide to 5-month-old baby development .

• Your little one is almost 5 months old! Celebrate a milestone moment by downloading these free printable keepsake cards for your next photo shoot.

• A play mat and age-appropriate toys.

• A few favourite baby books.

• Diapers, wipes, diaper rash cream, and a baby thermometer.

• For even more info, sign up to receive our emails: [insert sign up email field]

4-Month-Old Milestones Checklist

Remember that every baby develops on their own timeline, but here are some common 4-month-old milestones many parents observe around this time.Use this checklist as a general guide to celebrate your little one’s progress and spot areas where they may need more support:

• Holds head steady without support

• Pushes up onto elbows during tummy time

• Brings hands to mouth and reaches for toys

• Starts to roll from tummy to back

• Babbles and makes sounds like “ahh” or “ba”

• Turns head toward voices or sounds

• Tracks moving objects with eyes

• Recognizes familiar faces from a distance

• Expresses when they’re hungry

• May show early signs of teething (drooling, chewing).

If you have any questions or concerns, your healthcare provider can offer guidance and reassurance.

The Bottom Line

At 4 months, your little one is growing more curious, expressive, and responsive, turning everyday routines into shared moments of connection. From playful coos to stronger movements and deeper sleep stretches, this stage is full of discovery for both of you.

It’s also a time when questions come up: “Am I doing this right? ” “What should a 4-month-old be doing? ” You’re not alone in wondering. Keep in mind that every baby develops at their own pace, and what matters most is progress over perfection. Lean on your healthcare provider when needed and know that small moments—like tummy time or story time—go a long way in supporting your baby’s development.

As you continue to care for your little one, don’t forget to take care of the essentials too. The Pampers Club app makes it easier to save on diapers and wipes by offering personalized digital offers—because those daily choices matter, too.

_{How We Wrote This Article The information in this article is based on expert advice found in trusted medical and government sources, such as the American Academy of Pediatrics and the American College of Obstetricians and Gynecologists. You can find a full list of sources used for this article below. The content on this page should not replace professional medical advice. Always consult medical professionals for full diagnosis and treatment.}