If you are 14 and 6ft 3 your dad is 6ft 8 and your grandfather is 6ft 4 how tall wil you be?

Answer 1

Given that you're already 6'3", I would say that it's almost a certainty that you're going to be taller than your grandfather. But there are other family member you need to take into consideration, for example: your mother, your other grandfather and your grandmothers. A LOT of factors impact how tall a person will grow to be. For example, my mother is 5'3" and my father is 6'0", I'm 5'6", my one sister is 5'8" and my other sister is only 5'4". We all have the same genes but there's a big discrepancy between 5'4" and 5'8" so there are clearly other factors at play. It sounds like you have a good shot of getting to at least 6'6" but you have to take more than just your father and one grandfather's heights into account.