The collars in this section come in sizes teacup thru timber wolf. If you have any questions if your dog fits within these standard sizes, just visit this link which will explain to you how to measure your dogs next correctly: SIZING
Also, the American Kennel Club and Jen Revies have pages packed with information on every dog imaginable and you can see what size your dog is (note, like us humans, even dogs of the same breed can be different sizes). Here are links: AKC and Jens Reviews