Convert Pennyweight (pwt) to Petagram (Pg) instantly.
About these units
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.
Petagram (Pg)
A petagram, equal to 10¹² kilograms, is used almost exclusively in global environmental science and earth system modeling. Planetary-scale carbon budgets—for example, the total carbon stored in Earth's soils or forests—are expressed in petagrams. The Amazon rainforest alone holds on the order of 100 Pg of carbon. Using petagrams helps researchers track changes in Earth's climate balance and evaluate feedback loops in the carbon cycle.