1.) Chest: Measure girth around the broadest part of the chest.

2.) Back length: Measure length of pet's back from the base of neck to the base of the tail.

3.)Neck: Measure the circumference of pet's neck for a snug fit as you would with a collar.

The most important is the chest size, so if the chest size is ok the other will not be big matter.

For the best fit, match the below dimensions to your pet's measurements as closely as possible. If your pet falls somewhere between two sizes, we advise ordering the larger of the two.