Convert Stone (st) to Petagram (Pg) instantly.
About these units
Stone (st)
The stone equals 14 pounds, or approximately 6.35029 kilograms, and is commonly used in the United Kingdom and Ireland for expressing human body weight. It has deep traditional roots, originating from stones used as counterweights in early commerce. Although largely replaced by metric units in most applications, the stone remains emotionally and culturally significant for personal weight expression in the UK. Many people find it more intuitive and relatable than kilograms due to long-standing social habits. The stone's endurance highlights how measurement systems reflect cultural identity as much as mathematical convenience. It is one of the few units still commonly used in conversation but not in scientific or industrial contexts.
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.