As many people who are buying shoes online, I was very hesitant. I read almost all the reviews before I finally decided to make my purchase. I wear a Size 5 -5 1/2 shoe and I know how hard it is to find a shoe that fits right. So I went with the Size 5 and it fits perfect " like a glove" as someone else mentioned on another review.  So my recommendation is that if you wear a 5 to a 5 1/2 shoe go with the  Size 5 and if you wear a 5 1/2 to a 6 get the Size 6. They are light weight and great for all the sliding and twisting and turning, such a big difference from a regular sneaker that sticks to the ground. They made a big difference on my knees which were giving me lots of problems with my other sneakers.  I have a high arch so I had to put in a insert for arch support but I have to do that with all my sneakers so I wasn't surprised.  I am a very happy girl with my first pair of Zumba shoes.