Overview

Children usually progress in a natural, predictable sequence from one developmental milestone to the next. But each child grows and gains skills at their own pace. Some children may be advanced in one area, such as language. But they may be behind in another area, such as sensory and motor development.

Milestones usually are grouped into five major categories: physical growth, cognitive development, emotional and social development, language development, and sensory and motor development.

Physical growth and development

Most children by age 3:

• Have gained about 4.4 lb (2 kg) and grown about 3 in. (8 cm) by their third birthday.
• Look more like a child than a baby. The belly is less rounded and the head and legs look more in proportion with the body.
• Have a complete set of baby teeth.

Go to www.cdc.gov/growthcharts to see the high and low percentiles for normal weight and growth.

Thinking and reasoning (cognitive development)

Most children by age 3:

• Know their own name, age, and gender.
• Follow 2- to 3-step instructions, such as "pick up your doll, and put it on your bed next to the teddy bear."
• Grasp the concept of "two." For example, they understand when they have two cookies rather than one. But they usually aren't yet able to understand the concept of higher numbers.
• Memorize a string of numbers rather than actually count. The same is true of the alphabet. A child may say the letters from memory. But a child may not be able to recognize a written letter singled out from the others. Yet, some 3-year-olds show great interest in and ability with numbers, counting, and the alphabet.
• Enjoy working with puzzles that have 3 or 4 pieces. Most children can also sort objects by shape and color.
• Have active imaginations and a rich fantasy life. For example, they may imagine that their toys or stuffed animals can talk and play with them.

Emotional and social development

Most children by age 3:

• Have a wide range of emotions.
• Separate easily from their parents.
• Express affection openly. They may show affection for familiar playmates spontaneously.
• Understand the concept of "mine" and "yours." They may have trouble sharing toys at times. Or they may have conflicts when playing with others.
• Can identify a person as a boy or girl. But they don't yet fully understand the distinctions between genders.
• Are interested in toilet training. Many stay dry when they are awake.

Language development

Most children by age 3:

• Learn new words quickly. Most recognize and can name common objects.
• Use plurals, such as "books" for more than one book. And most children use pronouns (I, you, me, we, they) and use complete sentences of 4 to 5 words. Strangers understand most of what they say.
• Often ask "why" and "what."
• Understand most of what they hear.
• Aren't yet able to fully express their feelings with words.

Sensory and motor development

Most children by age 3:

• Develop more large muscle movements (gross motor skills). Most children can:
  • Run.
  • Climb. Most children alternate feet when going up or down stairs.
  • Jump in place.
  • Pedal a tricycle.
  • Kick a ball.
  • Bend over easily.
• Develop more small muscle coordination. This involves their hands and fingers (fine motor skills). For example, most children can:
  • Copy a circle.
  • Use a cup, fork, and spoon with ease.
  • Get dressed. But they usually still need some help managing buttons, zippers, and snaps.
  • Turn the pages of a book one at a time.
  • Build a tower of 6 blocks.
  • Hold pens and pencils using thumb and forefinger.
  • Screw and unscrew lids.