I work in a clothing store where we sell panties and my best advice would be to measure your hips and add an inch to two if your not tapeing. That will give you the most realitive size when looking on a label. From there you can transfer your knowledge of what size you are to a small, medium, large, etc but it will vary by who makes it. It will usually be best to ask someone or view a sizing chart if you know your size, and hip width. Hope that helps and happy shopping!