Convert Poundal (pdl) to Kilogram (kg) instantly.
About these units
Poundal (pdl)
The poundal is the unit of force in the foot–pound–second (FPS) system, defined as the force that accelerates a one-pound mass at one foot per second squared. Although a force unit, it interacts with mass units in engineering contexts similarly to inertial mass units. Historically, poundals appeared in older physics textbooks and engineering references before the widespread adoption of SI units. Their use has declined dramatically, but they remain part of the history of classical mechanics education. The poundal exemplifies how many different systems attempted to rationalize force, mass, and acceleration before the international community converged on the SI newton.
Kilogram (kg)
The kilogram is the base unit of mass in the SI system and the only SI unit defined directly by a fundamental constant rather than a physical object. Originally, its definition was tied to a platinum–iridium artifact stored in France—the famous "International Prototype Kilogram." Over time, tiny mass changes in the prototype and its official copies created difficulties for high-precision science. In 2019, the kilogram was redefined using Planck's constant, linking mass to the laws of quantum physics through the Kibble balance. This innovation ensures universality, stability, and reproducibility across the world. The kilogram is central to commerce, science, engineering, and every quantitative field dealing with matter. Its decimal relationships with other metric units (grams, milligrams, tons) make it universally convenient. From groceries to spacecraft mass budgets, the kilogram anchors modern mass measurement.