About Torque Conversion
Torque conversions are essential for automotive maintenance, machinery, and engineering applications.
Torque units
Torque is a force times the distance from the pivot. The SI unit is the newton-meter. One foot-pound (more precisely a pound-force foot) is 1.3558 N·m, one inch-pound is 0.11298 N·m, and 12 inch-pounds make a foot-pound. A kilogram-force meter, found in older metric manuals, is 9.80665 N·m.
Converting a torque spec
Torque wrenches are often marked in only one unit, so specs need converting. A lug-nut spec of 100 ft·lb is 100 × 1.3558 = 135.6 N·m. A spark plug spec of 25 N·m is 25 ÷ 1.3558 = 18.4 ft·lb, or 221 in·lb. Small fasteners and bicycle parts are usually given in N·m or in·lb because the values are low.
Torque is not energy
A newton-meter of torque has the same base units as a joule of energy, but they are different quantities. Torque describes a twisting force, while energy is work done. That is why torque is written N·m and energy J, and why this converter keeps them separate.