SIZE Guide: Measure the chest at its widest point all the way around for CHEST Girth; Measure length of pet's back from the base of the neck to the base of the tail for BACK Length (Excluding the tail). We recommend one size up for comfort if your dog's measurement is the higher end of the range listed. Always choosing the size by the measurement of your pet (The chest girth and back length),not the weight or breeds simply. For jumpsuit with legs, we should pay attention to both chest girth and back length. Size Chart:
Size X-Small: Back Length 7 inches, Chest Girth 11 inches, Neck Girth 7 inches;
Size Small: Back Length 8.2 inches, Chest Girth 12 inches, Neck Girth 9 inches;
Size Medium: Back Length 10 inches, Chest Girth 14 inches, Neck Girth 10 inches;
Size Large: Back Length 10.5 inches, Chest Girth 17 inches, Neck Girth 11 inches;
Size X-Large: Back Length 12 inches, Chest Girth 19 inches, Neck Girth 12 inches.