The AKC Breed Standard is 17 - 20 inches at the shoulder. The weight ranges from 30 to 45 pounds. I have a female that weighs 37 pounds at 19 inches tall and a male that weighs 45 at 19 inches...
Like all new born pups, a shepherd will fit in the palm of your hand. It is when they grow that it gets tricky . . . expect them to grow exponentially, especially in the first few days.
A normal, purebred Australian Shepherd will generally fall within the sizes listed on the Aussie breed standard. A male is generally 20-23 inches high at the shoulder, and a female is 18-21 inches...