How this calculator works
Both units use the pound-force, so the only difference is the lever arm. One foot is exactly twelve inches, which means one foot-pound is exactly twelve inch-pounds. The newton-metre readout uses the exact international pound-force and inch definitions.
Formula
foot-pounds = inch-pounds / 12. inch-pounds = foot-pounds x 12. N-m = lbf-in x 0.1129848290276167 = lbf-ft x 1.3558179483314004.
Worked example
24 lbf-in = 2 lbf-ft = 2.71164 N-m. 100 lbf-ft = 1,200 lbf-in = 135.582 N-m.
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Frequently asked questions
Is a foot-pound the same as a foot-pound of energy?
No. The torque foot-pound is force times lever arm. The energy foot-pound is force times distance moved. They share a name and dimensions but describe different quantities, which is why torque is sometimes written lbf-ft and energy ft-lbf.
Which unit should a torque wrench use?
Use the unit printed in the equipment maker's specification. Converting does not change the target torque, and a wrench calibrated in one unit may be harder to set precisely in another.
Why do small fasteners use inch-pounds?
Inch-pound values are larger numbers than the same torque in foot-pounds, so a scale can show finer steps. A value of 90 lbf-in is easier to read on a small wrench than 7.5 lbf-ft.