I purhcased these in brown.  I normally wear a 7 1/2, so I tried on both a size 7 and an 8.  I bought the size 7.  I almost always wear an 8 when only whole sizes are an option, so I was surprised.  I've read that other people have purchased 1/2 size up, but not me.  The soles are squishy, so that 3" heel is probably more like a 2 1/2 or 2 3/4" heel, since the soles "squish" down when you put weight on them.  I walked to the grocery store and back last night in my new sandals, and they were very comfortable.