Torque Converter

Convert torque between newton-metres, pound-feet, pound-inches and kilogram-force metres.

How to use this calculator

  1. 1Enter the value you want to convert.
  2. 2Pick the unit you are converting from and the one you want.
  3. 3The table below shows the same value in every other supported unit.

How the calculation works

result = (value × factor(from) ) / factor(to)
factor
How many newton-metres one unit represents

Every value is converted to newton-metres first, then out to the target unit. This means n units need n factors rather than n² conversion pairs.

Torque is force multiplied by the perpendicular distance to the pivot, so every torque unit is a force unit times a length unit. That is why the conversions are simply the force factor multiplied by the length factor.

Torque and energy share the same dimensions (force × distance) and both come out in newton-metres, but they are different physical quantities. Energy in newton-metres is conventionally written as joules precisely to keep the two apart — a 10 N·m torque is not 10 joules of anything.

"Foot-pounds" is ambiguous in casual use: as torque it is lbf·ft, as energy it is ft·lbf. Same numbers, different quantity.

Worked example

100 pound-foot to newton-metre

  1. 1.One pound-foot is 1.3558179 newton-metres, so 100 lbf·ft is 135.58179 newton-metres.
  2. 2.One newton-metre is 1 newton-metres, so divide: 135.58179 ÷ 1 = 135.58179.
  3. 3.Put another way, 1 lbf·ft = 1.3558179 N·m.

Result: 135.58179 N·m

What this assumes, and where it stops

Assumptions

  • Conversion factors follow the internationally agreed definitions of each unit.

Limitations

  • Results are computed in double-precision floating point, which is exact to about 15 significant figures.
  • Very large or very small values are displayed in scientific notation to avoid misleading precision.

Common questions

Are foot-pounds of torque the same as foot-pounds of energy?

Numerically identical, physically different. Both are a force times a distance, but torque is a twisting effect about an axis while energy is work done along a line. The convention is to write torque as lbf·ft (or N·m) and energy as ft·lbf (or joules) to keep them distinct — a torque wrench reading 100 lb-ft has not done 100 ft-lb of work.

Why do some specs use inch-pounds instead of foot-pounds?

Because small fasteners need small numbers. A spec of 0.8 lbf·ft is awkward; the same value as 9.6 lbf·in is easier to read and to set on a torque wrench. There are exactly 12 pound-inches in a pound-foot, so converting is straightforward — but mixing them up by a factor of 12 is a common and expensive mistake.

Formula and content last reviewed on .

Results are estimates for information only, not professional advice.

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