Carat is often misunderstood as the measurement of the size of a diamond. In fact, carat is the measure of how much a diamond weighs. One carat is defined as 200 milligrams.
Carat is the standard unit of measurement for weighing diamonds and other gemstones across the world. The carat system allows for very precise measurements as each carat can be subdivided into 100 points. This is very crucial as a slight difference in weight can have a considerable impact in the value of the diamond.
The weight of a diamond no doubt affects the size of the diamond but depending on shape, weight distribution and cut quality, two diamonds of the same Carat weight can look different in size.