I've purchased taller boots.  It's very cute and has nice shape for rain boot. I got size 6 and is my usual size but it was tight that I can wear it only barefoot or with nylons. If you are  planning to wear it for gardening or walking your dog in the rain, I would go a half size larger.  But wait!  They don't come in half sizes.  Try one size larger.  One more thing... I thought they were heavy.

Update:  My size seemed to be popular that I finally found the right size and pattern.  It is rather heavy for what it is.  But it became one of my favorites.  Love them!