when i had horses you were able to make a rougth estimate on how big the foals would make by a simple formula.
obviously it helped if you knew the height of the parents and the bloodlines ect.

i was wondering thougth if there was a way of finding out roughtly in the same way the estimated height of a pup.

obviously it mkae sno diffrence to me how big benji grows, ill love him all the same.

however a few experienced dog owners i hear them say oh he is going to be a big boy. but how can they tell just by looking at him?

I think they continue to gain height until about 8-12 months depending on the breed (GSD if i'm correct , my goldens mature about the same way soo..) After a year they start to fill in , most dramtically the first to the second year and then little by little there whole life.

you can tell by the paws , dogs will 'grow in' to there paws so big paws usually means big dog. Comparing with other dogs , ask around other GSD owners about weight and age you can get a rought estimate of how big your dog will be compared. Also the size of the head but GSDS usually have humongous heads to begin with :p