• Behavior
  • Education
  • Health

By age 3, your little one’s brain will be 80 percent of its adult size!

  • Posted
Father helping young boy put on boots

In this article, you’ll find answers to questions like:

1. Should all kids develop at the same rate?
2. What percentage of kids are at risk for delays?
3. Who can help?

By 2 years old, most toddlers are able to walk up steps, turn book pages, form simple sentences and put on clothing.

If your child isn’t, perhaps it’s something to consider. The earlier developmental delays are identified and addressed, the better the outcome for the child will be.

As parents, we often hear the term developmental milestones and know it’s important our children hit these markers at key moments of growth. But what exactly do child development specialists mean by that phrase?


“First, it’s important to remember that every child is an individual,” says Randee Gabriel, Children and Family Services manager at 211 Palm Beach/Treasure Coast. “There are no two children that will hit every milestone at the exact same time. Still, there are crucial cues to look for at each age.”

Gabriel explains children up to age 5 should reach milestones in how they play, learn, speak, act and move (see chart below).

“This is because a young child’s brain develops incredibly quickly,” says Gabriel, adding a newborn’s brain is about a fourth the size of an adult brain. By age 3, the brain grows to 80 percent of adult size on its way to 90 percent by age 5.



Gross motor

Fine motor

Cognitive, linguistic and communication


1 year

Stands alone; pulls self to stand; takes steps with or without support

Puts block in cup; picks up objects with finger and thumb; points

Imitates vocalizations/ sounds; babbles; says single words

Waves hi or bye; imitates activities; plays pat-a-cake; follows simple commands

2 years

Throws ball overhand; jumps up; kicks ball; walks up steps

Stacks towers of four to six cubes; turns book pages

Says 50 words; names pictures; combines words; follows simple instructions

Puts on clothing; removes garments; uses pretend items in play




3 years




Balances on each foot; jumps on one foot




Wiggles thumb; copies lines and circles; stacks towers of six to eight cubes; strings large beads




Speaks more clearly; names colors and pictures; names seven body parts




Names friends; brushes teeth with help; uses words to describe emotions (happy, sad)


One in four U.S. children up to age 5 are at moderate or high risk of developmental, behavioral, or social delay, according to the U.S. Centers for Disease Control and Prevention. In addition, many children experience delays in language or other areas that can affect school readiness.

“Every age group brings within itself new changes and skills required,” Gabriel says. “While a child may have no concerns at 6 months, this does not guarantee there will be no concerns at 25 months or 48 months or beyond. Rescreening at each interval is imperative to identify these shifts and ensure healthy development over the long term.”


Detection and intervention are critical for optimal outcomes for children. If you have questions or concerns about your child’s development, call the 211 Help Me Grow Program. Help Me Grow services are free, including screenings, information and resource connection. 


• Randee Gabriel, Children and Family Services manager, 211 Palm Beach/Treasure Coast
Centers for Disease Control and Prevention, U.S. Department of Health and Human Services
Mental Health Association of Palm Beach County


Back to listing

For a listing of all resources, click here.
Additional Resources
You May Also Enjoy
  • Help! My baby or toddler won’t calm down

    • Change positions to provide new things for your baby to look at. • Move your toddler from a stressful situation to a quiet place. • Calming skills foster positive and healthy relationships for a lifetime.

  • Five steps for stopping a temper tantrum

    Five tips for stopping a temper tantrum in its tracks.

  • Build your toddler’s foundation through reading

    • Reading with your child is a great way to show your love. • Singing songs and reciting nursery rhymes is another way to learn words. • The library offers free activities for all ages, such as play groups.