A shoestring and measuring tape or ruler works in a pinch, too. Take the shoestring or measuring tape and wrap it round your dog’s neck between the ears and the collar bone, the place your canine will wear his collar. Add 2 inches to this measurement, and you have your dog’s neck dimension.Harness match is also essential. Measure the neck and across the body at the deepest point of the chest. Many harness firms additionally use weight to guide sizing.