A dog door is one of the most beneficial and helpful inventions, both for the dog as well as its owner. It gives the liberty of free movement to the dogs, indoors and outdoors. It also allows the owner to do their share of work, without having to worry about the movements of the dog constantly. To purchase the most appropriate sized dog door, a few steps have to be thoroughly followed.rnrnThe width of the dog has to be measured. Usually, the widest part of the dog is measured. For most dogs, it is their shoulders.rnHowever, some may also have a wider chest or hips.rnThe height of the dog has to be measured. The height of the dog can be measured by starting from the top of their shoulders andrnmeasuring right down to their paws.rnThe weight of the dog has to be calculated. The weight has to be considered to ensure that the door is sturdy and strong enough to withstand the dog without wearing off.rnA cardboard cut out can be used as a dummy to ensure that the dogs can move across it without any hassle.rnFinally, the size of the door can be chosen according to the appropriate size of the cardboard cut out. Different brands have different size charts. It is essential to know the correct specifications and the measurements of both the door and the dog.