To get the most accurate size harness for your pet, measure the girth of their chest, around the widest part of your dog's torso right behind the front legs, with a cloth tape measure. Pull the cloth tape snug, but not tight. If you don't have a cloth tape measure, you can use a piece of string and measure it with a rigid ruler afterwards. Make sure there's enough room for about two fingers between the harness and your pet's chest for comfort.
| Size || Chest Girth |
| Small || 10.24 to 14.17 inches |
| Medium || 13.39 to 22.05 inches |
| Large || 18.9 to 25.98 inches |