If you ever wanted to work out the total carat weight of a loose diamond or multiple diamonds, then all you need to know is that 1 carat is equal to 0.2 grams. To calculate the carats of a loose diamond, first, you weigh the stone and record its weight in grams. Then, divide that number by 0.2 and you will have the total carat weight of that diamond.
It also works in reverse, if you wanted to work out the actual weight of a diamond or of multiple diamonds, multiply the carat weight by 0.2 and you’ll have the corresponding total weight in grams.