This headband is one size fits most and the size cannot be adjusted. The headband is sewn at a 6.5" diameter (13" circumference), keep in mind that measurement is before it stretches. We feel this is the perfect size for our soft material to fit a newborn and stretch comfortably as she grows into childhood. The bow measures approximately 4.5" across. The FAB headband is wider that our Classic styles, unrolled the width measures approximately 5".