How many grams in one carat?

Answer 1

A "carat" can be two things:  it can be the weight of a diamond, or it can be the percentage of gold which is pure.  Due to the weigh you asked the question I have to assume you mean diamonds, and not gold.

The easiest way to remember it is like this:  there are 5 carats to a gram.  So if your ladyfriend got a 5 carat engagement ring, she'd have one whole gram of high quality carbon on her finger.  (Wow!)  But for most of us peasants that's an impossible dream, a 1 carat diamond (0.2 grams) is the best they can hope for.

A previous answer giving "0.02 grams or 200 milligrams" is an obvious typo, it should read "0.2 grams or 200 milligrams".