Torque Converter

Multiply the newton-metre value by 0.7376 to get pound-feet, since one N·m equals 0.7375621 ft-lb. Going the other way, multiply pound-feet by 1.3558 to get newton-metres. So a 100 N·m spec is about 73.8 ft-lb, and a 90 ft-lb spec is about 122 N·m. This converter does both directions live, and shows in-lbs and kg-cm at the same time so you never have to chain two conversions.

Both measure torque, but the lever length differs: a foot-pound is a one-pound force acting a foot from the pivot, and an inch-pound is that same force just an inch out. Because a foot is 12 inches, one ft-lb equals 12 in-lbs. Small fasteners and electronics are usually specced in in-lbs, while lug nuts and engine bolts use ft-lbs, so mixing them up can over-tighten a part by twelve times.

Torque equals force times lever length, so the pull you need is the torque divided by the wrench length in the same unit system. Convert the target torque to newton-metres, put the wrench length in metres, and divide to get the force in newtons; divide newtons by 4.448 for pounds of pull. A 100 N·m bolt on a 0.3 m wrench needs about 333 N, roughly 75 lb of steady pull at the very end of the handle.

Because torque is force multiplied by length, a longer handle multiplies your pull. Double the wrench length and you halve the force needed for the same torque, which is why a breaker bar loosens a seized nut a short ratchet cannot. The flip side is that a long bar makes it easy to overshoot a torque spec, so for final tightening a calibrated torque wrench beats brute leverage.

Kg-cm, sometimes written kgf·cm, is a metric torque unit common on servos, small motors, RC gear, and electronics from Asian manufacturers. It means the force of one kilogram acting one centimetre from the centre. One kg-cm equals about 0.0981 N·m or 0.0868 in-lb, so it is a small unit; a hobby servo rated 10 kg-cm produces roughly 0.98 N·m. The converter includes it so datasheet numbers translate straight across.

Only if your wrench is scaled in a different unit than the spec. A wrench that reads in ft-lbs cannot directly dial a spec given in N·m, so convert first, or the fastener ends up loose or over-torqued. Enter the spec here in whatever unit the manual uses and read off the unit your wrench shows. Always tighten to the value, then stop, rather than guessing by feel.

No. Force is a straight push or pull in pounds or newtons; torque is a twisting effort, force times the distance from the pivot, measured in N·m or ft-lbs. Horsepower is different again, it is the rate of doing work, and it depends on torque and rotational speed together. This tool converts torque units and finds the linear force at a chosen wrench length, but it does not calculate power.

Most passenger cars call for lug nuts between about 80 and 100 ft-lbs, which is roughly 108 to 136 N·m, but always check the figure in your owner's manual because it varies by wheel and stud size. Tighten in a star pattern in two or three steps, and use a torque wrench for the final pass. This converter is handy when a manual lists the spec in N·m but your wrench reads in ft-lbs.