The newton (N) is the SI base unit of force, defined as the force needed to accelerate one kilogram of mass at one meter per second squared. Named after Isaac Newton, it is the fundamental unit in mechanics, structural engineering, and physics worldwide. One newton equals approximately 0.2248 pound-force.

Pound-force (lbf) is the standard imperial unit of force in the United States, defined as the gravitational force exerted on one pound of mass at sea level. It appears in bolt tension ratings, material testing, and mechanical engineering specifications throughout North America. One pound-force equals approximately 4.448 newtons.