One of the greatest sources of confusion in the Imperial (or U.S. Customary) system of measurement is that both mass and force are measured using the same unit, the pound. The differentiate between the two, we call one type of pound the pound-mass (lbm) and the other the pound-force (lbf).

What is lbf equal to?

An lbf, or a pound force, is the gravitational force exerted by a matter on the surface of the Earth. ... In figures it looks like this, 1 lbm x 32.174049 ft/s2, or equivalent to 32.174049 ft. lbm/s2. Thus if we convert it to “N,” or Newtons, then it is just 1 lbf = 0.45359237 kg x 9.80665m/s2 = 4.4482216152605 N.

What is the difference between lbm and LBS?

The pound mass, abbreviated lbm, is a unit of mass which is defined as 0.453 592 37 kilogram. The pound force unit, abbreviated lbf or simply lb, is a unit of force equal to that exerted by one pound mass under the gravitational acceleration at the earth's surface.