Liz,
The heel height is measured from the mid point on the heel tip straight up to where it joins the sole of the shoe , not at the back of the heel . There is a Youtube video explaining the details .
Also there is a natural heel height which explains why some people can wear heels or not . Sitting on the floor with your back supported and legs straight out if your feet drop away at an angle you can wear heels , if your feet are at right angles to the floor it's not recommended you wear heels . To assess your natural heel height assuming your feet drop away , take a line from the ball of the foot at a right angle to the floor , from that line measure the distance to where the heel touches the floor . My measurement is 3.5" and I must admit I'm most comfortable wearing heels of 3.5 " . I have 4" and 5" heels which I can dance in but my feet let me know all about it the next day . I have very few flat shoes , only ones that I walk the dog in and work in the garden .
