Follow the sizing recommendations for the
product. When fitting for a harness you will want to
measure your dog's girth. This is the measurement around your dog
(circumference) just behind the front legs. You are looking to measure your
dog at his or her widest part. Take a tape measure and start at the back then
run the tape measure straight down underneath your dog and back up until you
reach the beginning of the tape. This will give you your dogs' girth size.