Convert Milligram (mg) to Pennyweight (pwt) instantly.
About these units
Milligram (mg)
A milligram is one-thousandth of a gram and essential for measuring extremely small masses with precision. Pharmacology relies heavily on milligrams to dose medications safely and consistently—especially potent drugs where differences of a few milligrams can be critical. In chemistry and laboratory science, milligrams are used to weigh reagents, catalysts, micro-samples, and test materials. Environmental science uses milligrams per liter or milligrams per kilogram to describe concentrations of contaminants. Its small size makes the milligram ideal for fields requiring strict quantitative control, and its stability within the metric system ensures predictable conversions during calculations.
Pennyweight (pwt)
The pennyweight, equal to 1/20 of a troy ounce or 1.55517384 grams, is a unit used primarily in the precious metals and jewelry industries. Its origins lie in medieval English coinage, when the weight of silver pennies provided a practical standard for small masses. Jewelers continue to use the pennyweight because many traditional pricing structures and metalworking conventions are built around troy-based subdivisions. For gold, silver, and dental alloys, the pennyweight remains easier to work with than grams due to long-established norms. Even though the metric system is now dominant scientifically, the pennyweight persists because industries tied to history—especially those involving money and precious goods—tend to maintain deeply rooted practices.