Sizing Information:
Tiny 3: up to 6 lbs., 12-14" Chest
Tiny 4: up to 8 lbs., 14-16" Chest
X-Small: up to 10 lbs., 15-17" Chest
Small: up to 15 lbs., 18-20" Chest
Medium: up to 20 lbs., 22-24" Chest
Large: up to 30 lbs., 25-29" Chest

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

Neck: Measure the circumference of the pet's neck for a snug, not tight fit.

Chest Girth: Measure the broadest part of the chest and add 2" for ideal fit.

Note: If the dog has a stout build, select one size larger.