benji (GSD DOG ) is coming on for 4 months old now. he has grown quite a bit since i got him at 13 weeks. i was wondering when do puppys reach there adult height,.and if there was any way of determing how big they will be when they have fully grown.

there is a GSD bitch who we meet at the park she is a fully gorn 5 year old and i consider her to be a fair siaze. but benjis paws are bigger than hers.

does that mean he may be bigger than the bitch?

Dogs are generally noticeably bigger than bitches so yes, I'd expect him to be bigger than her. The standard says the ideal height for dogs is 63cm (25") at the withers. (The ideal height for bitches is 2 inches smaller.) A dog is also likely to be proportionately more muscular, so will appear to be even bigger than he actually is.
:)

I don't know about GSDs; btu I do know dobes are generally between half and 3/4 their adult height at 6 months old.  They are a similar height to GSDs, so I imagine it will something similar.  He'll keep growing upwards till he's between 12 and 18 months I would think, though he'll be filling out for a while after that.

Would this go for Rotties as well?  Our puppy is already half the size of 3 adult gilrs in the park and she is only 4 months old. Her paws are pretty big too.

My cousin has 3 gsd's mother father and baby (ha ha) the baby who is 9 months old is already head and shoulders above dad and his paws are massive the vet says to step up his food as he has another growth spurt to come. He was the only pup in the litter and was big at birth we think it will be the zoo shortly i am sure there is a bit of a lion about him. The funny thing is he is white the parents are not but the dads dad is white aswell he looks really funny a giant compared to my wee westies.