MEASURE YOUR DOG Measure your dog from the COLLAR to the base of the tail. Always measure twice to assure a good fit. The kilt comes in even sizes. If your dog is broad chested, or has no waist, order the next size up. Example: measures 17'' and is slightly overweight, order a size 18'' If your dog is a trim 17'' order a size 16'' If your dog measures in even sizes order true size unless overweight. NOTE: The average Westie is 14" but, of course, some may be smaller or larger.