Every dog bootie is different. Each has its own shape, style, and design that will work in varying ways to fit comfortably onto your dog's foot. Because of this, there is no one way to measure for the perfect fit, however, we have checked each and every product recommended here and they all have their own measuring and fitting guides. Once you have selected the boot that is perfect for your needs, please visit the product website for information on the best way to measure for sizing.