In most cases, formal dress will run smaller than casual clothing sizes. In regards to size, you will need to compare your measurements to the size chart provided from the designer for each dress. You must consider your body type and the style of the dress. The size chart is merely a guide to assist you in selecting the size that is best for you. Sometimes a dress might need alterations for the perfect fit. Also, provided on each size chart is a YouTube video to display how to have your measurements taken if needed!