I wear 36" pants so I assumed a medium belt (33-36") would fit. The center strap is 40 inches when unstretched but needs to be stretched to 41 inches so I can secure it around my waist. I wear 36" pants so this is a bit confusing for me. A large 37-40 inch belt can fit loosely around my waist. Of course you can stretch the large strap for a tighter fit if needed. The large strap is approximately 44 inches long when unstretched.