16". I posted once on the ASK CATHE forum about reducing the size of my calves (should I give up step, calf training, etc?) and Cathe responded with something that changed my way of thinking. She said that she, personally, would never sacrifice the power of the calf muscle in order to achieve a smaller size. My calves may be huge, but the allow me to jump higher, run faster, step for longer, etc. I'm beginning to like them.