Units:

Torque has dimensions of force times distance. Official SI literature suggests using the unit "Newton meter" (N m) or "Joule per radian". The unit Newton meter is properly denoted "N m" or "N·m", but not other combinations.

(this avoids ambiguity—for example, mN is the symbol for millinewtons, nm is the symbol for nanometers, etc.)

The joule, which is the SI unit for energy or work, is dimensionally equivalent to a N m, but this unit is not used for torque. Energy and torque are entirely different concepts, so the practice of using different unit names for them helps avoid mistakes and misunderstandings. The dimensional equivalence of these units, of course, is not simply a coincidence: a torque of 1 N m applied through a full revolution will require an energy of exactly 2p joules. Mathematically,
where......
E is the energy t is torque ? is the angle moved, in radians. (This equation motivates the alternate unit name of "Joules per radian".)

[Other non-SI units of torque include "pound-force-feet" or "foot-pounds-force" or "inch-pounds-force" or "ounce-force-inches" or "meter-kilograms-force" or "kilogrammeter" (kgm). For all these units, the word "force" is often left out, for example abbreviating "pound-force-foot" to simply "pound-foot". (In this case, it would be implicit that the "pound" is pound-force and not pound-mass.)