Baby Growth Calculator

This simple calculator allows you to see how the weight and height (length) of an infant compare to other infants of the same age.

It uses percentiles for the task of comparison. A percentile indicates the value at or below which a certain proportion of a population falls. This isn't as difficult a notion as it sounds (though it should be said there is no universally accepted definition of percentile). For example, if your baby's weight is at the 55th percentile, it means that 55% of the population weigh the same or less than your child (and 45% of the population are heavier).

This tool will calculate the percentiles for an infant's weight and/or height (length) relative to other infants of the same age and sex. The data comes from the World Health Organization.

The Calculation

To do this calculation, you'll need to know the infant's weight and/or height, sex, date of birth, and date of the measurement (i.e., the age of the infant when they were weighed or measured).

First, you need to select whether you want to know about the infant's weight, height (length) or both? (Press Submit when you've made your choice).

Please Select... Weight Height (Length) Both

Disclaimer: It is important to understand that this calculator is provided for educational purposes, and shouldn't be treated as a diagnostic tool. If you have any concerns about the rate at which your child is growing, then you should consult a medical professional.