I bought these for both of my kids, who are 10 and 5. I had to size up half a size for my 10-year-old, but my little guys regular size fit well.

I also bought a pair for myself and sized up half a size and they were too big (I have narrow feet.) If you are between sizes and have a wider foot, I would recommend sizing up a bit. If your feet are narrow, your regular size may work.