How do you know how tall you will be when older?

Using this equation: If you are male: average your birth parents heights and add 2.5in. If you are female: average your birth parents heights and subtract 2.5 inches. This is your predicted adult height. This is a general guideline and can impacted based on if you are healthy as you are growing (if you are getting enough nutrients, exercise, sleep). Also, it may change based on when you go through puberty.

No gurantee!: Look at your mother and look at your father, look at your older siblings and at your grandparents and aunts and uncles. That will give you a pretty good idea but no gurantee. Discuss with your pediatrician, family physician or pcp at your next wellness visit.