Coat size is determined by measuring the length of your dog's back from the nape of the neck to the base of the tail, and the circumference around your dog's neck, and the circumference around your dog's chest, and the circumference around your dog's waist.
Be sure your dog is standing squarely, with head up, while measuring.
With your dog looking straight ahead, measure from the point where the neck joins the body to the point where the tail joins the body.
Measure around the deepest part of your dog's chest and also around the waist just in front of the upper thigh, and measure around your dog's neck at a point just above the nape.
You can use this table to find an approximate size, although we do recommend measuring your dog to find the best fitting coat.