4-month-old baby milestones

As your baby turns 4 months old, they are likely making their personality—and opinions!—known to you. And there is no sweeter way to know you are doing the right thing than a baby’s smile or laugh. As your baby eagerly observes and works on engaging with the world around them, you can support them with some thoughtful play activities and plenty of love. They are learning constantly—whether you two are on a walk around the block, snuggling up at bedtime or reading together.

It’s helpful to have a baseline understanding of 4-month-old milestones, so you can track progress and consult with your pediatrician if you have any questions or concerns. Here’s what you can look forward to this month.

4-month milestones at a glance

As your baby emerges from the fourth trimester, they may seem more ready to engage with the world. From having fun with toys to starting to laugh (the sweetest sound!), your little one is likely beginning to work on moving and grooving a bit too. They might be pushing up on their arms from a tummy-down position and reaching and grabbing for anything (and everything) they want. Sleep starts to consolidate a bit more these days—they’re spreading out their naps and feeding times slightly more, as well. And don’t worry: If you’re fretting about the notorious 4-month sleep regression, we have a helpful reframe for you.

Related: 4-month sleep regression: What every parent needs to know

An in-depth look at 4-month milestones

Your little one may be mastering some major motor skills this month, like holding up their head (what a strong neck!) and using their arms to push up. All of this is in preparation for their first big move: rolling over, which should start to happen soon. Get the camera ready!

4-month developmental milestones

Here’s what The American Academy of Pediatrics (AAP) and Centers for Disease Control and Prevention (CDC) say about 4-month-old baby milestones.

(Editor’s note: The 4-month milestone guidelines were written to reflect the behaviors that 75% or more of children exhibit at a certain age. Note that milestones are not a perfect metric: It’s key to speak to your pediatrician if you have concerns about your unique child.)

Senses

• Your baby knows the difference between tones of voice—which is why they react one way when you speak in soothing, calming tones and another way when there are surprising noises.
• Your baby’s vision has improved to about 20/40 and they are able to better distinguish colors. Their eye coordination has also improved, so bring it up with their doctor if they still seem unable to focus on objects within close range or cross their eyes.
• You may notice your little one turns their head when you speak to them and smiles, laughs and makes sounds to get or keep your attention.

Gross motor skills

• At 4 months, some babies are working on (or already quite good at!) rolling over. Babies generally roll from stomach to back first.
• Look out for that first pushup—baby may be able to push up on their forearms or elbows from a tummy-down position.
• With good head control and improving trunk strength, your baby may be able to sit with support. Just be sure to supervise them in this position—they’re still not quite strong enough to sit by themselves just yet.

Fine motor skills

• Your baby has gotten pretty good at grabbing and picking up objects—although they won’t use the more advanced pincer grasp for another few months.
• Your baby has better control and coordination over their hands, and may hold a toy in their hand and use their arm to swing at toys.

Related: ‘Follow the child’: How a Montessori mantra changed my motherhood

Baby’s sleep at 4 months

At 4 months, your baby has officially graduated from newborn to infant. Congrats! They need slightly less sleep than they did in the newborn days—but it’s still a lot: The American Academy of Sleep Medicine notes that, on average, infants aged 4-12 months need 12-16 hours of sleep per day, including naps. But the biggest change that happens this month? Melatonin production kicks in—which can come with some sleep shifts, also known as the 4-month sleep regression.

But don’t stress, says certified baby sleep consultant Rachel Mitchell. “This is often the stage that parents start to dread the anticipated ‘4-month sleep regression,’ but what is actually happening is that your baby is making big leaps developmentally and this is more of a progression,” she says. “While progressions will likely affect your child’s sleep habits, there is no need to panic. This is a lot for your baby to go through at once, so consistency in this stage is key.”

Reframing the regression as a progression can hopefully help make this period a little less trying. Now’s the time when you want to start setting up a more regular sleep schedule and a consistent bedtime routine to go with it. Talk to your doctor about dropping one nighttime feed or starting to sleep train, if you’re interested.

Related: Gentle sleep training saved my marriage

What baby sleep looks like at 4 months:

• Your baby may be taking 3 to 4 naps per day
• Your baby may be sleeping in 3- to 6-hour windows at night
• Your baby may be awake for 90 to 120 minutes at a time

Read more: How much sleep does a 4-month-old baby need?

Feeding a 4-month-old

Whether you’re breastfeeding, formula-feeding or combination feeding, you’re surely now a pro at recognizing and responding to your baby’s feeding cues. Those cues are hopefully starting to become more aligned around a schedule, now, as well—and more of something you can start to plan on (and around).

The AAP and La Leche League (LLL) recommend the following feeding timeline and amounts for 4-month-olds:

• Breast milk: 4 to 6 ounces every 3 to 4 hours
• Formula: 4 to 6 ounces every 4 hours

You’ve still got a couple months to go before introducing solids (not until 6 months!), but if your child is deemed by their doctor to be at high risk for developing severe food allergies, introducing some allergenic foods at 4 months may be recommended. Be sure to talk to your child’s pediatrician to discuss and learn more.

Read more: 4-month-old baby feeding schedule & amounts

4-month-old health & growth

In month four, you can expect your baby to grow another 0.8 inches (about 2 centimeters), and possibly double their birth weight. You can expect your baby to gain another 1 pound to 1.25 pounds this month.

How much does the average 4-month-old weigh?

According to the WHO:

• A 4-month-old baby boy in the 50th percentile weighs 15 pounds, 7 ounces (7 kilograms) 
• A 4-month-old baby girl in the 50th percentile weighs 14 pounds, 2 ounces (6.4 kilograms)

How long is the average 4-month-old?

According to the WHO:

• A 4-month-old baby boy in the 50th percentile is 25 1/4 inches long (63.9 cm)
• A 4-month-old baby girl in the 50th percentile is 24.5 inches long (62.1 cm)

Read more: 4-month-old baby health & growth guide

Activities for 4-month-olds

Is your little lovebug suddenly chatty? Many babies will start babbling and repeating some sounds around the 4-month mark, and it can be so fun to watch them become mini conversationalists. But don’t worry if your little one hasn’t started making sounds just yet. Remember that milestones are just general guidelines but not hard-and-fast rules. Still, talk to your doctor about any concerns.

Here are a few activities to do with a 4-month-old baby:

Expand their world. If you haven’t yet signed up for baby storytime at the library or got a playdate under your belt quite yet, now’s the time. Your tiny tot is ready to soak up more social outings.

Hide and seek. Embrace baby’s new understanding of object permanence with games like Guess Which Hand, Hide-and-Seek with toys, and Peek-a-Boo.

Mix in mirrors. Make tummy time more fun by setting up a small hand mirror by baby’s playmat. Babies love to see themselves! Tell them, “See the baby? Hi sweet baby.” Point to their nose, mouth, ears, and name each body part.

Read more: Activities for a 4-month-old: Fostering baby’s development

Our favorite products for 4-month-olds

Zutano

Booties

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$22

Chances are you’ve lost at least one sock or bootie by now. Save yourself the headache next time and snag a pair of classic Zutano booties. Their award-winning styles are hands down the best booties. What could possibly make these different than others? Well for starters, they actually stay on baby’s feet! They feature two snaps so you can be sure to get a secure fit every time–snug enough your little Houdini can’t wiggle them off, but not so tight as to be dangerous. They come in tons of colors, patterns and fabrics so you can have a pair to match any outfit in any season!

 

SHOP

Itzy Ritzy

Silicone Teething Mitt

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$8.99

Just pop this cutie over their little hand and they’ve got a teether that requires just enough dexterity. The textured silicone on top soothes sore and swollen gums and the crinkle sound it makes keeps baby entertained.

SHOP

Vulli

Sophie La Giraffe

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$25.37

Does it look like a fancy glorified dog toy? Yes. Does it also possess some freakish ability to calm, soothe and entertain (almost) any baby who gnaws on its squeaky head and hoofs? Also yes.

SHOP

Supporting your 4-month-old baby’s development

Ready to make the most of those wake windows? These 4-month-old baby activities can support your cutie’s development.

• Soothe your 4-month-old baby by responding to their emotions rather than always trying to dismiss or distract them.
• Play with your 4-month-old baby by putting some objects just beyond their reach during tummy time. This can help motivate them to roll and eventually crawl.
• Engage your 4-month-old baby’s senses with multisensorial toys that use sounds, colors and textures—like the Glow and Discover Light Bar.

Related: Montessori fosters ‘wellbeing’ through life—and these Montessori toys help you start at home

It’s science: Your baby knows what your hug means

Like a language without words, your baby is getting a loud and clear message when you hug them—even as young as 4 months old. As researchers have shown, babies know the difference between a comforting hug and just being held to be carried or fed. Why does that matter to you? Babies who feel loved and supported also benefit cognitively and developmentally.

A note from Motherly: 4-month milestones

When you’re talking about your baby’s developmental milestones, it’s natural to talk about the love and care they feel in the same breath. So, yes, working on tummy time, reading books and singing songs can all do wonders for your 4-month-old’s development—but be sure you fill in with a lot of snuggles, too.

Look ahead: 5-month-old baby milestones

A version of this story was originally published on Oct. 16, 2021. It has been updated.