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Foot-Pounds to Newton-Meters

ft-lb to Nm

ft-lb

Convert foot-pounds (ft-lb) to newton-meters (Nm) using this calculator tool. Although the technically correct term for torque is pound-force foot (lbf·ft), we use the more familiar 'ft-lb' format (we discuss our reasons for this further down the page). Note that we also have a separate converter for Nm to ft-lb (or you can use the switch button in the calculator above).

Foot-Pounds to Newton-Meters Chart
ft-lb Nm
1 ft-lb1.356 Nm
2 ft-lb2.712 Nm
3 ft-lb4.067 Nm
4 ft-lb5.423 Nm
5 ft-lb6.779 Nm
6 ft-lb8.135 Nm
7 ft-lb9.491 Nm
8 ft-lb10.847 Nm
9 ft-lb12.202 Nm
10 ft-lb13.558 Nm
20 ft-lb27.116 Nm
30 ft-lb40.675 Nm
40 ft-lb54.233 Nm
50 ft-lb67.791 Nm
60 ft-lb81.349 Nm
70 ft-lb94.907 Nm
80 ft-lb108.465 Nm
90 ft-lb122.024 Nm
100 ft-lb135.582 Nm
Note: conversions are rounded to max 3 decimal places.

Disclaimer: Whilst every effort has been made in building our calculator tools, we are not to be held liable for any damages or monetary losses arising out of or in connection with their use. Full disclaimer.

How to convert ft-lb to Nm

One foot-pound (ft-lb) is equal to 1.356 newton-meters (N·m), rounded to 3 decimals. To convert foot-pounds to newton-meters, multiply your figure by 1.356. Note that although it's frequently expressed as ft-lb or foot-pounds, the unit is technically lbf·ft.

What is a foot-pound?

A foot-pound (pound-foot) is a unit of torque from the Imperial/US customary system and is equal to 12 inch-pounds. It represents the torque produced by 1 lbf applied at a perpendicular distance of 1 foot from the pivot.

Note: We express pound force as lbf in the definition above in order to distinguish it from lb mass, though you'll also see lb-ft commonly used in automotive specifications.

Pound-foot and foot-pound

As we mention in our newton meters to foot-pounds conversion page, there has been much debate about whether it is correct to use foot-pounds when referring to torque. At the beginning of the 20th century, over 125 years ago, British physicist Arthur Mason Worthington proposed the idea of using "poundal-foot" (pound-foot) to reduce confusion with foot-pound, which is a unit of work or energy. He wrote this in his book Dynamics of Rotation' while he was headmaster and a professor of physics at the Royal Naval Engineering College in Devonport:

"Since in the British absolute system, in which the pound is chosen as the unit of mass, the foot as unit of length, and the second as unit of time, the unit of force is the poundal, it is reasonable and is agreed that the British absolute unit of torque shall be that of a poundal acting at a distance of 1 foot, or (what is the same thing, as regards turning) a couple of which the force is one poundal and the arm one foot. This we shall call a poundal-foot, thereby distinguishing it from the foot-poundal, which is the British absolute unit of work." – Arthur Mason Worthington, 1900

It's an idea that the Society of Automotive Engineers concurs with. As Greg Acosta of EngineLabs explains, they have adopted pound-feet or (or pound-force foot) as the industry standard unit of engine torque.

The industry standard for measuring an engine’s power output is SAE Standard J1349, which is the standard adopted by SAE to specify a basis for net engine power and torque ratings. “SAE standard J1349, Table 1 lists the units of measure used in the standard as “N-m or lb-ft” for torque and “kW or hp” for the horsepower ratings,” says Gary W. Pollak, P.E., Program Manager for the Society of Automotive Engineers. 2

Despite the technical preference for lb-ft, we use the more familiar ft-lb format in our converter and reference table because ft-lb is more common in practical applications like automotive manuals, torque specifications, and torque wrench markings.

Calculator by Alastair Hazell.

References

  1. A.M Worthington. Dynamics of Rotation.
  2. EngineLabs. Pound-feet or foot-pounds–which one is it?.