This is a handy app that allows you to calculate the weight, length, head circumference, and BMI of your child at any given age. These calculations are based on the latest data from the World Health Organization (WHO) and the United Kingdom (UK) Department of Health. 

It is a one-off app, so there is no need to store any data. It is a quick and easy way to get the weight, length, head circumference, and BMI of your child at any given age.

It is useful for health professionals who need to calculate the weight, length, head circumference, and BMI of a child to determine if there is a need for further medical investigation.