How big do border collie blue heelers get?

I have a border collie blue heeler and I think he has a little pointer in him Cause he loves to stop and point, anyway his name is Nike, and he is almost just about a year old and he is and agility dog and loves to play but I looked online on google and they all look like medium sized dogs. Well he still looks like maybe 6-8 months old and I have no idea why!? I really like big dogs and medium so I am trying to get him as big as possible! Thanks!!

He's a mixed breed so there is no way to tell until he becomes an adult.

They would probably be on the medium-small side because the Blue Heeler is a smaller breed, and the Border Collie is about medium to medium-small.

Heelers are fairly smallish medium, typically 30-38 lbs. I fostered one who was 34 lbs, and the vet said she was the perfect weight and size for a cattle dog. Border collies vary a bit. There's small BCs that are only 25-35 lbs. There's also some large ones closer to 45-50. So, there's really no way to say how big your dog would be.A pointer is a a bigger dog, so if he has pointer in him, he could be bigger than either of those breeds. How tall is he right now? If he's nearing a year old, his bones are just about done growing, since for most breeds, dogs reach their full height around 12 months of age. So, he's probably just about there. After his bones are done, he'll keep filling out in muscle until about 18 months. You can probably expect him to gain another 6-10 lbs in muscle.I have a mixed breed 19" tall at the withers. I adopted him at 12 months of age. At that time, he was very lanky and slender, and you could tell that he hadn't grown into his body yet (like a teenager who just hit puberty and is suddenly really tall and skinny), he weighed 26 lbs then, and the vet said this was the perfect weight for a 12 month old. He now weighs 34 lbs (6 months later), and the vet said he's filled out with really nice muscle tone but has not gained any fat. I don't know if knowing about my dog will help you, but maybe he's about the same size.