About Newborn, Infant, Baby, and Toddler Age Ranges and Stages

From the moment of birth to the first day of preschool, your little one may be referred to as a newborn, baby, infant, or toddler. But when does your little one graduate from being a newborn to becoming a baby, and when does toddler age start? While there are no fixed definitions or age ranges for the terms, newborn, baby, infant, and toddler, we've put together some useful information to help you differentiate between these stages and understand the developmental changes that typically occur during each phase.

Newborn, Baby, and Infant Age

You may have heard your new bundle of joy being referred to as a newborn, infant, or baby. Many parents wonder, what is considered newborn, how long is a baby considered a newborn, and how old is an infant? Although some of these terms can be used interchangeably, as there’s no set age range, some experts use newborns for those under 28 days of age, while other experts apply the name newborns to little ones up to 2 months old or even 3 months of age. So, a newborn age range can extend from birth to around 1 month, 2 months, or 3 months of age. However, your little one can also be referred to as a baby or infant during this time, up until they’re about 1 year old.

Child Developmental Stages: Newborn, Baby, Infant Age

Every child is unique and develops at their own rate, but in your little one’s first year, you can expect some big leaps in their growth and development. Here are some exciting developments that you may notice by the time your baby is 1 year of age.

• Their first smile

• Your newborn’s vision becoming more focused and being able to see colours and objects in the distance

• Reaching out for items

• Starting to understand certain words, such as “no,” and recognizing the names of people

• Waving “bye-bye!”

• Babbling or saying “mama” or “dada”

• Developing bonds and trust with loved ones and caretakers

• Playing games, such as peekaboo or patty-cake

• Crawling or pulling themselves up to stand

• Walking along while holding onto furniture

• Possibly taking their first steps

• Developing fine motor skills, such as the pincer grasp, picking up small objects using their thumb and pointer finger.

As your little one grows and transitions from a teeny tiny newborn into a more active baby, it’s natural to wonder if their development is on track. Every baby is unique and meets milestones at different rates, so don't hesitate to contact your baby's healthcare provider if you have any questions or concerns about their development.

related baby tool

Baby Growth Chart Calculator

Keep an eye on your baby’s height, weight, and head circumference to average growth with our simple tool.

Fill out your baby's details*:

What is your child*

Boy Girl

This is a mandatory field.

Age (months)

This is a mandatory field.

Weight (lbs.)

This is a mandatory field.

Height (in.)

This is a mandatory field.

Head circumference (in.)

This is a mandatory field.

Track your baby’s growth

*Input details of your baby’s last measurements **Source: World Health Organization

Toddler Age Range

It may feel like only yesterday that you were holding your tiny newborn in your arms, and now they’re an active baby who never stops moving! But what is a toddler, when and at what age is a baby/infant considered a toddler, and how old is toddlerhood? Most experts suggest toddlerhood starts at 1 year of age. This is the time when many babies are ready to "toddle"—to take those first shaky steps. The toddler age range runs from around 1 year (12 months) to around 3 years of age.

Child Developmental Stages: Toddler Age

In the blink of an eye, your newborn has become a toddler, and with that comes increasing independence and curiosity about the world around them. Get ready for some of the exciting and interesting developments that you may see during your child’s toddler years.

• Starting to walk and learning to walk alone and walk well

• Beginning to run

• Pulling their toys along behind them

• Kicking a ball

• Climbing

• Feeding themselves

• Imitating others’ behaviour

• Developing an awareness of themselves and understanding “mine” and “his/hers”

• Playing enthusiastically alongside other children

• Engaging in pretend play and make-believe

• Sorting by shape and colour

• Following two- or three-step directions

• Saying four- and five-word sentences.

Every child develops and meets these milestones on their own timeline during their toddler years, so be prepared for your child to take more or less time than other children of the same age. If you have any concerns about your toddler’s developmental progress, such as their walking or language skills, contact their healthcare provider.

Related Articles

Baby Growth Spurts: When Do They Typically Occur?

Preschool Age Range

Now that you have a rough idea of newborn, infant, baby, and toddler age ranges, what comes after a toddler? Once your toddler is around 3 years old, they are often considered a preschooler. The preschool age range may extend from 3 years up until they are around 5 years old. How time flies!

The Bottom Line

Although your little one may always be a baby in your heart, some common terms will be applied to them as they grow and develop. The term newborn is often used for babies under 28 days or even up to 2 or 3 months of age, according to experts. After this period (and even during the newborn stage), your little one may be referred to as a baby or an infant up until they’re around 1 year of age. But when does your teeny tiny baby become a toddler? Experts commonly use the word toddler when babies turn 1 year of age. The toddler age range usually runs from 1 year to 3 years of age, and before you know it, your little one will be a preschooler! Each of these stages brings its own exciting developmental milestones and learning curves for your child. So, enjoy the journey!

_{How We Wrote This Article The information in this article is based on the expert advice found in trusted medical and government sources, such as the American Academy of Pediatrics and the American College of Obstetricians and Gynecologists. You can find a full list of sources used for this article below. The content on this page should not replace professional medical advice. Always consult medical professionals for full diagnosis and treatment.}