Convert Grain (gr) to Microgram (µg) instantly.
About these units
Grain (gr)
The grain, defined as exactly 64.79891 milligrams, is one of the oldest units of mass still in limited use today. Derived from the weight of average cereal grains such as barley or wheat, it became a universal tiny unit used across Europe for coins, medicine, and gunpowder. The grain persists in firearms and ammunition manufacturing because bullet weights are still listed in grains (e.g., a "150-grain bullet"). Reloaders and ballistic engineers rely on the grain as a fine unit suitable for measuring powder charges and projectile masses. It is also used in traditional gold and silver transactions, linking it to the troy system. The grain's longevity highlights how ancient agrarian measures can remain embedded in modern technological practices.
Microgram (µg)
A microgram is one-millionth of a gram, essential in pharmacology, nutrition science, and chemical analysis. Many vitamins, especially fat-soluble ones like vitamin D and K, are prescribed or measured in micrograms, as exceeding recommended doses can be harmful. In environmental monitoring, pollutant levels—such as airborne particulate matter—are often expressed in micrograms per cubic meter. Researchers working with catalysts or rare biological compounds rely on microgram-scale measurements for precise experiments. The microgram is indispensable in fields requiring tight control over small masses that impact biological or chemical systems significantly.