Researchers have created a formula and online calculator they say can predict whether a newborn is at risk of becoming obese during childhood. The formula takes into account the baby’s weight, the parents’ weight, the number of people in the household, the working status of the mother, and her smoking habits during pregnancy.

Researchers from the Imperial College in London and Harvard University created the formula by looking at data from a study of nearly 4,000 children born in Finland in 1986. Those who had the highest risk of obesity, based on these measures, were most likely to become overweight or obese during their childhood and into their teen years.