Body measurements and the shirt dimensions stored in your Proper Cloth account are quite different. Chest Width, Midsection Width, Bottom Width, and Sleeve Width are all taken from a shirt laying flat on a surface. Thus, multiplying them by 2 will yield the actual circumference of the shirt in these areas. For other measurements such as Collar Size and Sleeve Length, the true measurements will be stored.
For example, heres how you would measure around your waist:
Compared to how we measure and store the Midsection Width dimension: