All 25karats rings are manufactured in US standard ring size. The most commonly purchased womens ring sizes at Blue Nile range from size K to N. USA US Canada and Mexico ring size system JPCHSA.
Select I dont know.
It shows ring sizes in both mm and inches plus internal diameter and external diameter. If you are looking for a ring as a gift for that special someone this process becomes twice as difficult especially if you wish for the ring to be a surprise. Imagine a lady who wears size 7 sneakers and size 8 dresses being told that her finger size is 53. If the size is wrong simply send in your ring within 90 days of your purchase and we will resize.