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.

The dyne (dyn) is a centimeter-gram-second (CGS) unit of force equal to exactly 0.00001 newtons, used primarily in physics for small-scale force calculations. It represents the force needed to accelerate one gram of mass at one centimeter per second squared, and appears in surface tension and electromagnetic force measurements. One dyne equals exactly 10 micro-newtons.