What Is an Infant? Age Range, Milestones & Development

What is considered newborn age?

A newborn is typically defined as a baby from birth up to about 1 month (0–28 days). This period is also called the neonatal stage and is focused on early adaptation to life outside the womb, including feeding, regulating body temperature, sleep patterns, and initial bonding with caregivers.

What is the difference between infant vs newborn?

A newborn is the earliest stage right after birth, while an infant includes the broader period up to 12 months. Infants show more development in movement, communication, and interaction compared to newborns. In other words, “newborn” refers to the first few weeks, while “infant” covers the entire first year of life.

When are babies considered toddlers?

Babies are generally considered toddlers from around 12 months to 3 years of age. This stage begins when walking and early independent behavior start to develop, along with increased curiosity, mobility, and early language development.

How old is an infant considered and when does infancy end?

Infancy usually lasts from birth to 12 months of age. After that, the child transitions into the toddler stage. During infancy, rapid physical, cognitive, and emotional development occurs, laying the foundation for later childhood growth.

What is an infant up to 6 weeks old called?

A baby from birth to about 6 weeks is still considered a newborn or neonate in early infancy. This is a critical adjustment period where feeding routines, sleep cycles, and basic physiological stability are still developing.

How long is a baby an infant?

A baby is considered an infant from birth until their first birthday (0–12 months). This period includes major milestones like rolling, crawling, and early speech. It is one of the most rapid stages of development in human life.

What’s considered an infant in terms of milestones?

Infants are defined by developmental progress such as head control, sitting, crawling, and early communication. These milestones gradually build toward walking and more complex social interaction by 12 months, with variation depending on each child’s individual development pace.