Foot-pound Force

Foot-Pound Force (ft·lbf): Understanding a Unit of Torque

The Foot-Pound Force, often abbreviated as "ft·lbf," is a unit of torque commonly used in the United States customary and British imperial systems of measurement. It quantifies the rotational force or torque applied when one pound of force is exerted at a distance of one foot from the pivot point or axis of rotation.

Definition and Significance

The Foot-Pound Force is defined as the amount of torque produced when a one-pound force is applied at a perpendicular distance of one foot from the pivot point. It is a fundamental unit of torque and is used extensively in mechanical and engineering applications, particularly in the United States and the United Kingdom.

Applications of the Foot-Pound Force

The Foot-Pound Force has a wide range of practical applications, including:

  • Mechanical Engineering: Engineers use foot-pound force to specify and evaluate the torque requirements for various components and systems, such as engines, gears, and machinery.
  • Automotive Industry: Torque measurements in ft·lbf are essential for designing and evaluating the performance of engines and vehicle components.
  • Construction: Construction professionals use torque specifications in foot-pound force when assembling structural components or machinery.
  • Manufacturing: Manufacturers rely on foot-pound force to ensure that products are assembled with the correct level of torque to prevent over-tightening or under-tightening of fasteners.
  • Physics: The unit is used in physics to analyze the effects of forces on rotating objects and understand rotational dynamics.


Conversions involving Foot-Pound Force are important for various applications:

  • 1 Foot-Pound Force (ft·lbf) ≈ 1.35582 joules (J)
  • 1 Foot-Pound Force (ft·lbf) ≈ 1.28507 Newton-meters (N·m)
  • 1 Foot-Pound Force (ft·lbf) ≈ 0.001285 kilogram-force meters (kgf·m)


The Foot-Pound Force (ft·lbf) is a fundamental unit of torque widely used in mechanical and engineering fields to quantify rotational forces and effects. It is essential for ensuring the proper functioning and performance of mechanical systems and components, particularly in the United States and the United Kingdom.

Keywords: Foot-Pound Force, ft·lbf, torque, rotational force, engineering, mechanical systems, joules