The reference and confusion comes in because of the vast similarities between the two dogs and the common ancestry. There are some great differences in the appearance of the Sheltie and the Collie though. The main difference is the head of the Sheltie and its size. It is long, and more squared off, not narrow or pointed and long as the Collie. The Sheltie also of course is smaller than the Collie with the standard for the breed being from 13 to 16 inches in height at the top of the shoulders and weighing from 14 to 25 pounds whereas the male Collie is from 22 to 26 inches at the shoulder and weighs from 50 to 75 pounds.
Bitches are generally smaller thus the broad range of size and weight.
Sheltie bitches generally run from 13 to 14 inches, weigh from 14 to 22 pounds and males 14 to 16 inches, and weigh from 20 to 25 pounds for the standard. The Sheltie is very well loved also for its lovely soft and thick coat and colors. From the most common sable and glossy black colors to the marbled merle colors of diluted black or sable, each with white markings. These colors are also, of course, the same colors that you will find in a Collie. The sable can be a pale or deep gold or have black mixed in.