Babies Average Weight by Age Revealed

Average baby weight is not the same as typical weight, as babies come in all shapes and sizes, just like adults.

According to the report, using a weight chart can help track a baby’s growth, and the Centers for Disease Control and Prevention (CDC) recommends using the World Health Organization (WHO) weight chart for babies up to 2 years of age.

The World Health Organization states that the average birth weight of a full-term male baby is 7 pounds 6 ounces, or 3.3 kilograms, while the average birth weight of a full-term female baby is 7 pounds 2 ounces, or 3.2 kilograms.

At delivery, experts consider a low birth weight to be less than 5 pounds 8 ounces, or 2.5 kilograms, regardless of whether the baby is full term or born earlier.

Babies usually lose some weight during the first week after birth, mostly due to fluid loss, and most gain it back without concerns.

Baby Weight Charts

Weight charts can help someone understand what percentile their baby’s weight falls into, and the chart below shows baby weights in the 50th percentile, which refers to the average weight.

Male babies tend to weigh a little more than female babies, so the chart divides by sex.

Babies usually gain weight most rapidly during the first 6 months of their life.

Typically, breastfed babies gain weight more slowly in their first year than formula-fed infants, which can be a natural part of their development.

It’s common for babies to lose weight in their first week of life, but they usually gain it back by the time they are 2 weeks old.

Weight Gain Patterns

Although this can vary, babies tend to double their birth weight between the ages of 4 and 6 months and may weigh triple their birth weight by their first birthday.

Growth patterns do not follow a clear schedule, and some babies gain weight steadily, while others gain weight rapidly, signaling a growth spurt.

This may move a baby into a new weight percentile, but it’s essential not to focus on weight as the only indicator of physical development.

Other measurements, such as the baby’s length and head circumference, are also important, and considering all three gives doctors an idea about how the baby is growing compared to other babies of the same age and sex.

For more information about developmental milestones, various checklists are available, including one from Pathways.org, which has endorsement from organizations such as the American Academy of Pediatrics (AAP) and the National Association of Pediatric Nurse Practitioners.

Several factors can influence a baby’s weight, including whether the baby consumes breast milk or formula, and underlying health issues can cause a baby to gain weight more slowly.

Babies born prematurely may weigh less during their first year than babies born at full term, but they tend to grow parallel to the curve of growth charts.

Regular checkups with a pediatrician are essential in a baby’s early stages of life to assess their growth and development.

A pediatrician will advise how often they should see a baby, and it can be helpful to keep notes on a baby’s growth and development to review during appointments.

Parents or caregivers can discuss any concerns about the baby’s growth or development with a pediatrician, and it may be beneficial to speak with a pediatrician between checkups if there are any major concerns.