3 Month Old Baby Milestones And Development – New Parents Guide


By three months, your little bundle of smiles will probably start to develop a personality of his own. You will find him inspecting his hands more and watching their movements. He will turn when you speak, and might even try to talk back in his way. You may find him reaching for objects too and most importantly, he may sleep through the night. Yay!

These 3 month old milestones are just a drop in the bucket. More is coming. You are just at the beginning of an exciting period or what most parents would call ‘the enchanted months’.  Perhaps this is a good time to get your baby acquainted with toys for 3 month olds, new faces, and new textures. 

This guide describes all the changes and developments to expect in your 3 month old. Let’s dive in!

What You Should Know

  • At 3 months, the baby may start sleeping for longer stretches at night time or even sleep through the night. This means better sleep for you too.
  • Many babies will make their first loud laugh at around 3 months old. It’s one of the most exciting 3 month old baby development stages you don’t want to miss. 
  • Look for signs that the baby is ready to eat solid foods. Most babies start eating solid foods as early as 4 months. 
  • Even if your baby is already sleeping through the night, it is advised that you continue room-sharing until he is at least 6 months old. 
  • Don’t worry if your baby can’t seem to get his thumb off his mouth. Thumb sucking is completely normal at this age, as your baby discovers his hands and fingers. 

The Most Adorable 3 Month Old Milestones

The first 12 weeks after the baby is born are usually referred to as the ‘fourth trimester’ simply because there is still so much growth and changes happening during that period. Your little person may have experienced some serious challenges adjusting to this new world, but as the third month comes to an end, you will notice a lot of remarkable developments in him. 

Exactly what milestones should my 3 month old be doing, you may ask? 

Your 3 month old will stop being too fussy in the evenings and grow into a happier, more smiley baby. Also, as mentioned, you probably won’t have to worry about helping your baby sleep through the night because he will start sleeping for longer periods. Below are more 3 month old milestones you should watch for. 

1. Weight And Length 

If you are a new parent, you may be wondering, “What is the normal weight for a 3 month old baby? “How much should he measure?” A healthy 3 month old baby should weigh about 14.2 pounds for boys and 12.8 pounds for girls, and the average length (height) should be about 24.1 inches for boys and 23.4 inches for girls. 

Whether your baby is close to this weight/length or not, what’s important is to make sure he is hitting his 3 month old baby development milestones at a healthy rate. He will probably have gained a pound and a half or two from last month. His height may have increased by an inch or an inch and a half too and his head grown by half an inch. 

It is common for babies at this age to experience a growth spurt. Growth spurts are commonly characterized by crankiness, hunger, or fussiness, and should be nothing to worry about. Just let baby eat and sleep enough or give more skin to skin if that is what he seems to want. Growth spurts are temporary; you will have your happy, smiley baby back soon enough.

2. The Senses

At this age, your baby’s senses will have developed significantly.


By now, the baby should be able to follow moving objects and focus on objects close to his eyes without eyes crossing. Also, he can recognize your face and make eye contact with you. 

But how far can a 3 month old see, you may wonder? Well, even though your baby’s vision has developed at this age, he can only recognize objects that are less than 18 inches away. Your baby’s depth perception is not fully developed, hence he still can’t judge how close or far away objects are. 


The hearing clarity of your baby has increased and you will see him turn toward loud sounds and try to imitate you when you speak.  


Baby is becoming more aware of his hands now. He has preferences to surfaces that feel smooth to touch like his swaddle blanket, your skin, and his face, and a dislike for surfaces that feel uncomfortable. 

But baby generally loves your touch. Carrying, stroking, rocking, massaging, and lifting your baby helps him relax and even enhances his attention and alertness span. If your baby is breastfed, he will have the opportunity to enjoy even more close time with you. 


At 3 months old, your baby can recognize your natural scent. While babies are born with this skill, it is one of the senses your baby uses now to know who you are.

3. Motor Skills

If you are wondering, ‘what are 3 month old babies supposed to be doing?’ know that at 3 months old, babies are more active and will therefore move and do a lot. Some of the things they will do include:

  • Imitating sounds, expressions, and movements
  • Raising his head and chest during tummy time 
  • Opening and closing his hands
  • Sucking his thumb and fingers 
  • Sitting up and holding his head steady when you place him on your lap
  • Bearing weight on his legs. You can test this skill by holding your little one in a standing position. 
  • Grasping and shaking toys around him
  • Smiling and vocalizing with lots of baby talk 
  • Showing excitement and anticipation
  • Stretching legs and kicking when lying on his back or stomach

Perhaps you are now looking at all of the things a 3 month old baby can do and wondering, ‘can my baby sit at 3 months?’ 

Yes, your baby can sit at 3 months but with support from mom or dad, a seat, or by propping himself upon his hands. How quickly a baby learns to sit varies from one baby to another but most babies will give it a shot between the age of 3 and 5 months. 

3 Month Old Food

As your baby grows, his appetite grows too. By now, you probably know how to tell when the baby is hungry. If you haven’t gotten the hang of things yet, don’t worry, your baby knows when he is hungry and he will let you know.

How Much Formula Should A 3 Month Old Drink? 

On average, a 3 month old should drink about 5 ounces of baby formula, 6 to 7 times a day. As we just stated, babies’ appetite grows with age. So if, for instance, you were using about 2 cans of formula per week in the first two months, you may want to increase that to about 3 or 4 cans a week. 

How Often Should You Breastfeed A 3 Month Old?

3 month olds should be breastfed about every 4 or 5 hours. However, breastfeeding is a little different from bottle feeding because you can’t measure how much milk your little one has consumed especially if he is getting it from the ‘source’. 

The most important thing is making sure the baby is content. Just let him suckle and he will pull away from the breast (and probably sleep) when he is full. If your baby is gaining weight steadily, then you are doing it right!

How Often Should A 3 Month Old Eat? 

A formula fed 3 months old should eat about 7 times a day, consuming 5 ounces each time. Breastfed babies should suckle about 5 times a day or on-demand. To make sure your baby is feeding enough, you can check his diapers. A properly-fed baby will have about 4 or 5 wet diapers per day. 

Many parents ask, “Is it okay to feed my 3 month old baby food?” Absolutely Not!  You should never feed a 3 month old baby food. Baby at this age is only able to eat formula and/or breast milk. Experts recommend starting babies on baby foods sometime between the age of 4 and 7 months. 

However, at 3 months old, some babies are ready for solids but it is not recommended. If you start you, baby, on solids before the suggested age, he will most likely develop food allergies or be at risk of obesity later on.  

Don’t give baby water until he is 4 months either. He is getting enough hydration from formula or breast milk already. Also, water will fill up the baby’s little belly and interfere with its ability to absorb nutrients and minerals from breast milk and formula. 

A Note On Breastfeeding Moms

At the age of 3 months, most parents will still be breastfeeding. However, as the baby grows, you may encounter breastfeeding challenges like going back to work, lack of breast pumps, drop in milk supply, or even a health condition whose medications are not compatible with breastfeeding. 

If you find difficulty breastfeeding, make sure to talk to your doctor. For health conditions that require you to take breastfeeding incompatible drugs, ask your doctor for nursing-friendly alternatives. In most cases, doctors will recommend breastfeeding-safe medications or substitute solutions until you are done breastfeeding. 

3 Month Old Sleep


The ability to sleep through the night is perhaps one of the most awaited 3 month old baby development stages. That means sleeping for about 7 or 8 hours straight. 

Whether you will also have a good night’s sleep will also depend on what time you put the baby to bed. If the baby goes to sleep, say, at 8 p.m. and gets up at 3 a.m., then it means your sleep will still be distracted. But it is still much better than in those newborn days. 

Apart from the prolonged stretches of sleep at night, most 3 month olds sleep an extra 4 ½ hours at daytime, split over 3 or 4 naps a day. Learning your baby’s sleeping cues can help you know when he is ready for bed and get him to sleep before he is too tired. Fussiness, rubbing of eyes, wanting to eat or nurse even when he is not hungry, could all be signs that baby is sleepy. 

Some parents think that making their babies sleep later at night will keep them in bed longer in the morning, but honestly, this is an ill-advised strategy. The truth is, when the baby stays up late, he gets overtired, and this could interrupt his sleep pattern, causing him to sleep less. 

If you want your baby (and you) to sleep more, stick to a consistent schedule. Have a specific time when you put your baby to bed both for daytime naps and for night sleep. 

When your 3 month old starts sleeping through the night, you may consider moving him to his room. However, the American Academy of Pediatrics (AAP) recommends that parents continue sharing rooms with their newborns until they are around 6 months old. Also, parents are advised to let their 3 month olds suck on a baby pacifier while they sleep to avoid putting them at risk of sudden infant death syndrome.  

There are many experts offering advice on how to handle a 3 month old and in particular how to get baby to sleep for longer stretches at night. Don’t ignore the advice but don’t ignore your instincts either. If the Ferber method (letting your little cry it out) is against what you believe in as a parent or just won’t work for your child, rule it out. 

A Day In A 3 Month Old Life

Many parents ask, “How do I stimulate my 3 month old baby?”

At 3 months, your baby will not have started talking much yet, and the best way to fit in his life and keep him stimulated would be to talk to him and play with him. In fact, according to the AAP, parents should sing, talk, and read to their newborns to help their brain and senses grow. 

If you don’t know what to say, begin by mentioning what you are doing or what is happening around you at any given moment. For instance, tell your 3 month old when you are changing his diaper, when you are preparing his food when you are about to bath him or get him dressed, etc. 

Mimicking the noises and sounds your baby makes, talking about things he seems interested in, kissing the baby, and getting excited when he responds to what you say can all help your baby learn. You also get to learn how your baby communicates in return. 

Do not let the baby watch TV at this age. Screen viewing before babies are 18 months old has been observed to have lasting negative effects in their short term memory, language, development, and reading skills. It has also been found to contribute to sleep and attention problems. 

Instead of screen watching, view family photographs with baby, make faces and imitate each other’s sounds, or show him how to play with his toys. 

When Should You Be Concerned?

Keeping track of your 3 month old milestones can be exciting, as you get to watch your baby change from a tiny little person to a ‘bigger’ person with a ‘bigger’ personality. However, it is important to note that babies are different and each will hit different milestones at different times.

Just because yours has not achieved a certain milestone at the time you expected him to doesn’t necessarily mean that there is something wrong with him. But if you are concerned, talk to your pediatrician. Make sure to note the following: 

  • If the baby is not eating properly or doesn’t seem to be adding any weight
  • If the baby does not appear to focus his eyes or eyes still cross when looking at close objects
  • If the baby does not seem to respond to loud sounds 
  • If the baby does not smile occasionally 

My Babies Planet Overview

Your baby has come a long way since the first day you held him in your hands. He is now 3 months old with wider smiles, better sleeping patterns, and more coordinated activities. Tracking your 3 month old milestones helps you appreciate the hard work you have put into bringing up your little person and the exciting changes you have seen him go through. 

Just don’t go too tough on the baby or get frustrated if he doesn’t achieve all milestones at the time you expect him to. Be patient and let things fall into place in their own time.

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Hello Mother's and Father's of the world. My name is Sarah Nielsen is this is my passion MyBabiesPlanet.com, as I am a mother of two beautiful babies and they are my world. Also I love blogging and sharing my experiences of what has worked for me when raising my kids. When I'm not juggling the madness at home, or working on my blog. You will find me product researching and keeping the site freshly updated with the latest baby gear and helpful articles for my readers!