These charts can be good for getting a rough idea of carat weigh and how it translates to size, but bear in mind that the actual spread of an individual diamond can vary. For example, some diamonds are cut very deep or shallow and can look small or large for their weight. So it is important when choosing a diamond to take note of the diameter measurements, if you are buying a 1 carat diamond, you want it to look like a 1 carat diamond! With fancy shaped diamonds such as pears, emerald cuts or Radiants, Princess etc, this can be more difficult to judge as cut quality with fancy shapes can vary tremendously.