Mg simply stands for milligrams, while Mcg is the abbreviation for micrograms. They both represent minute units of measurement in the metric system. They are used to indicate units of measurement for weight quantity, and also used in the mass measurement. The mcg is far smaller than the mg, and it is one of the smallest units of measurement in science. It is a millionth of a gram, and it is equal to 0.01 mg.
Mcg is usually used for tests of organisms or substances in biologies, such as antibiotics like oxacillin, penicillin, and others. Milligram, on the other hand, is also a small unit of measurement, but not as small as the Mcg. Milligram is a thousandth of a gram. Also, 1 mg is equal to 1000 mcg. This means that mcg is 1000 times smaller than mg. Milligram is frequently used in various sectors than micrograms due to its higher mass measurement.