A teenth is usually a term to describe a small amount of drugs. Usually when refering to buying a teenth, someone would be talking about meth amphetamine or crack cocaine. So how much does a teenth weigh? The real weight of a teenth is 1/16 of an ounce or 1.75 grams. As you can see this is not that much, but can cost you a lot depending on the drug you are buying.