Baby Growth Calculator

Where your baby sits (weight)

What this means

Growth percentiles compare a baby's weight and length against reference curves from the World Health Organization, which describe how healthy infants grow under optimal conditions. A baby at the 30th percentile is bigger than 30% of healthy same-age, same-sex babies and smaller than 70% — it's a snapshot of where they sit, not a grade. What matters most is the trend over time: steady growth along roughly the same channel is the reassuring pattern, while crossing many percentile lines warrants a provider's look.

Recommendations

• •Watch the trend across visits rather than a single reading — one point rarely tells the story.
• •Trust the range: anywhere from roughly the 3rd to 97th percentile can be perfectly healthy.
• •Discuss any concerns or percentile jumps with your pediatrician, who has the full growth history.

Watch out

• •This is an approximation of WHO curves, not a clinical tool. It doesn't replace measurements taken by a health professional.
• •Birth weight, prematurity and genetics all influence where a baby tracks — context matters.