Oval Carat weight explained 👇🏼 A 'Carat' refers to a diamonds measurement of weight, NOT size. Carat is a unit used to measure the mass of a diamond, with one carat equaling 200 milligrams. It's always good to remember Carat and Size are not same thing. The carat weight of your diamond doesn't directly translate to the physical size (length and width) of your diamond; other factors like cut and shape influence how big the diamond appears. For example, a one-carat oval diamond might look larger