Carat refers to a lab grown diamond's weight and gives you a sense of its size. The unit of weight for lab grown diamonds is the metric carat, which is one-fifth of a gram and is divided into 100 points. A bigger lab grown diamond doesn't always mean a more expensive one; you have to consider all the 4 C's.
Here's a tip: When you compare lab grown diamond carat sizes, consider a lab grown diamond's cut. A high-carat la grown diamond with a poor cut grade can look smaller, often featuring a deeper cut, rather than a lab grown diamond with a smaller carat and a far better cut.