There are several indicators that can give an idea of a child's height as an adult, although none of them can accurately predict adult height.
Genetics: The most important factor that determines a person's height is their genetics. The height of the child's parents and grandparents can give a general idea of the child's potential height.
Growth rate: The rate at which a child grows can give some indication of their potential height. Children who grow at a faster rate in their early years may reach a taller height as an adult.
Bone age: An X-ray of the child's hand can be taken to determine their bone age, which can give an idea of how much more the child will grow.
Height at a certain age: The height of the child at a certain age, such as two years old or four years old, can be used to estimate their potential adult height using growth charts and formulas.
However, it's important to keep in mind that these indicators are not foolproof, and many factors can influence a person's height, such as nutrition, exercise, and overall health. Ultimately, adult height is determined by a complex interplay of genetic and environmental factors.