Child development and milestones: your 42 month old

Child development and milestones: your 42 month old

At three-and-a-half years old, your little one is even more active, friendly, and constantly learning how to communicate and relate to the world. It's truly an exciting time filled with more memorable milestones!

Your three-year-old is now at the halfway point to their fourth birthday! And there are many 3-year-and-6-month-old milestones to get excited about now that your fast-developing toddler is well into what they call the “magic years.”

Though he likely hasn’t outgrown the tantrums characteristic to the terrible twos, he is starting to be able to manage his emotions and relate to his peers through play.

Your 3.5-year-old also loves to hop, skip, jump, and explore the world. This sense of wonder has a lot to do with his imagination, which is blossoming just as rapidly as his vocabulary at this age.

Ahead, we take a closer look at 3-year-and-6-month-old milestones for each aspect of development to help you get to know your not-so-little one better!

42 Month Old Development and Milestones: Is Your Child on Track?

42 month old development and milestonesPhysical Development

Your 3-year-and-6-month-old just loves running, jumping, hopping, rolling, dancing, and also has basic climbing skills. She can go up the stairs, alternating feet, while holding on to a rail. She can also throw and catch balls with both hands.

Aside from gross motor skills, kids this age are fond of activities that allow her to exercise dexterity, like unbuttoning clothes, stacking blocks and doing puzzles.

The typical height of a three-and-a-half-year-old is about 99 cm (39 inches) for boys, or 97.7 cm (38.4 inches) for girls. Average weight is about 15.3 kg (33.8 lbs) for boys, or 14.9 kg (32.8 lbs) for girls.


  • Bake a cake with your kid! Empower her to do helpful tasks while guiding her accordingly.
  • Play simple sports like kicking a soccer ball around and aiming for a net.
  • Engage her in activities that can improve dexterity, like arts and crafts.

When to Talk to Your Doctor:

  • Consult your child’s paediatrician if your child has extreme difficulty climbing up stairs or grasping balls.
  • Being unable to do activities that require dexterity, like grasping crayons and pencils, could also be a cause for concern.
Child development and milestones: your 42 month old

Knowing about 42 month old milestones can greatly help mums and dads guide their little one as he nears his 4th birthday! | Image courtesy: Shutterstock

Social and Emotional Development

Since your child has likely started preschool at this age, he is starting to be more comfortable with interacting with other kids. He can also be taught to put his toys away and not to snatch toys from other kids. Sharing is a good lesson to learn at this age.

When before the age of three he likely preferred parallel play, at 3.5 years old, he becomes less shy. Your not-so little one is beginning to establish friendships, choosing these connections with peers based on similar interests. But at this age, he can also happily play by himself. Imagination plays a huge role in playtime.

Watch out for occasional temper tantrums because they can still happen at this age, often when things don’t go his way.


  • Guide him when it comes to building things with his friends, through projects involving blocks, cardboard boxes, and fabric.
  • You can also boost his confidence and independence by asking him to match shoes or socks together.
  • Play dress-up! Role-playing can help nurture his imagination.
  • In the event of tantrums, your 3.5-year-old can already grasp and express certain emotions. Use this as an opportunity to teach him how to manage his emotions.
  • At 42 months old and beyond, kids start appreciating being included as part of routines, like grocery shopping and attending special occasions like birthdays.

When to Talk to Your Doctor: 

  • If your child is extremely clingy or refuses to be separated from mum, dad, or any other caregiver, this might be a cause for concern.
  • If your child’s tantrums are interfering with daily tasks, then consult a paediatrician to know how best to help your child manage overwhelming emotions.
Child development and milestones: your 42 month old

One of the most adorable 42 month old milestones is when your kid starts making friends based on similar interests, like swimming! | Image courtesy: Pixabay

Language and Cognitive Development

Your 3.5-year-old is swiftly learning how to communicate. At this age, she will already have an extensive vocabulary. Your child should also be able to learn words easily and incorporate them into sentences.

Grammar skills are also flourishing at this age. Verb tense, subject-verb agreement? Your child is getting the hang of these, too.

Child development and milestones: your 42 month old

One of the greatest 42 month old milestones is a flourishing, extensive vocabulary! | Image courtesy: Shutterstock

At 3.5 years old, kids can recognise numbers and distinguish them from letters. Though she might get confused by series of numbers and letters, her greatly improving memory should help her effectively recognise and repeat them back to you.

When it comes to her surroundings, 3-year-and-6-month-olds are becoming increasingly aware of how to distinguish and name objects. She can also identify patterns, and even grasp the concept of how things can grow and change — like how seeds can grow into flowers.


  • Communicate with your child by talking about how her day went. You can also play listening games like “Simon Says…”
  • Constantly ask her questions about daily tasks or experiences at school to exercise her ability to explain things.
  • Give her simple instructions with proper guidance, like where to put her toys away or how to wipe down a table after meals.

When to Talk to Your Doctor:

  • If your child struggles with forming sentences and basic grammar, this could mean you should pay a visit to your paediatrician.

Health and Nutrition

At 3.5 years old, kids generally have full bladder and bowel control, but the occasional slip-ups are still expected.

He can also put his shoes on, and he can brush his teeth in both horizontal and vertical motions.

It’s important to know that kids develop at their own pace. Just because your child isn’t hitting these 3-year-and-6-month-old milestones, it doesn’t meant there is something wrong or that he will always be lagging behind his peers.

At this age, he is beginning to grasp certain aspects of life, like eating healthy and taking safety measures — like not running with scissors or touching hot pans.

When it comes to nutrition, your child’s daily nutritional needs are about:

  • Boys: 1,532 Kcal/day
  • Girls: 1,437 Kcal/day 

Your child’s daily food intake should ideally consist of:

  • Carbohydrates

Your active child needs lots of energy to get through his/her busy day. Make sure he/she gets lots of carbohydrates from food like grains. Your child needs 4-5 ounces daily, half of which should be from whole-grain sources. 1 ounce equals 1 slice of bread, 1 cup of ready-to-eat cereal, or ½ cup of cooked rice, cooked pasta, or cooked cereal.

  • Protein

At this age, your child needs 3-4 ounces of protein daily. Meat is a great source of protein for the growing child, but there are also many other sources, including plant-based ones, such as beans, tofu or peanuts. 1 ounce equals 1 ounce of meat, poultry or fish, ¼ cup cooked dry beans, or 1 egg.

  • Fruits and Vegetables

Fruits and vegetables are the primary sources of vitamins and minerals for your growing child. So make your child’s plate full of fun colours to ensure that he/she is getting plenty of fruits and veggies. At this age, he/she needs 1-1½ cups of fruits and 1½ cups of vegetables every day.

  • Dairy

Dairy is an important source of nutrition for your little one. Your little one needs at least 2 cups of milk per day, but this could also be 2 cups of yogurt, 3 ounces of natural cheese, or 4 ounces of processed cheese.


  • Allow your child to dress themselves, or go to the bathroom to exercise his independence through self-care.
  • Include him in meal preparation, giving him easy and safe tasks that don’t involve wielding sharp utensils.
  • But make sure to constantly remind him of safety precautions at home and at school; he’s able to grasp these at this age.

Vaccinations and Common Illnesses

Ideally, your little one should have all of his/her vaccinations complete by this age. To find out what vaccinations your child should have got up to now, and check if this schedule is up-to-date, click here.

As a reminder, your child should already have the following vaccinations:

  • Chickenpox
  • MMR
  • Flu
  • Hepatitis A
  • Hepatitis B

If your child is missing any of these vaccinations, don’t hesitate to consult your doctor.

When to Talk to Your Doctor:

  • See your child’s paediatrician if he is unable to control his bladder or bowel movements.
  • If you’re concerned that your child is at risk for the flu, then it’s best to consult your child’s paediatrician regarding the necessary vaccination.

We hope this article on three-and-a-half year old child development is useful in keeping track of your little one’s milestones!

42 month old development and milestones



Republished with permission from theAsianparent Singapore


Sources: Livestrong, United Psychological Services, Foundation Years UK

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Bianchi Mendoza

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