Back length(green line) To do this, measure the length of the back line between the neck and the base of the tail using a flexible measuring tape. A good indication of the base of the neck is the bottom edge of a loose-fitting collar . When measuring, the dog should stand in a straight position and carry its head upright .
Chest circumference(orange line) To determine the chest circumference, measure the circumference of your dog's chest with a tape measurewidest or highest point .
Neck circumference (purple line) To measure the correct neck circumference, place a measuring tape around your dog at exactly the point shown. Two fingers should easily fit between the measuring tape and your dog's neck. Don't measure too tightly.