Which standard units are used to measure torque?

The measurement of torque is specifically expressed in units that convey the rotational force applied at a distance from an axis of rotation. Newton-meters (Nm) is a standard unit of measurement for torque in the International System of Units (SI). One Newton-meter is defined as the torque resulting from a force of one Newton applied perpendicularly to a moment arm that is one meter long. This relationship highlights the fundamental components of torque—force and distance—making Newton-meters a fitting unit for accurately measuring this physical quantity.

In contrast, other units mentioned do not accurately represent torque. Pound-feet (lb-ft) also can be used to measure torque, but it is primarily used in the United States customary system. Joules (J) are used to measure energy, and Pascal-seconds (Pa-s) are units of dynamic viscosity, reflecting how fluid flows rather than rotational force. Thus, while other units may relate to aspects of mechanics, only Newton-meters effectively capture the essence of torque in the SI framework.