Convert Torque from Pound-inches to Newton-meters (lbf-in to Nm)

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Single conversion

Pound-inch to Newton-meter Conversion Formula

To convert from Pound-inch (lbf-in) to Newton-meter (Nm), use the following formula:

Newton-meter (Nm)

= 112 × 1.355818× Pound-inch (lbf-in)

= 0.11298483333333333333× Pound-inch (lbf-in)

With 1.355818 is the ratio between the base units Newton-meter (Nm) and Pound-foot (lbf-ft).


Example

Let's convert 5 Pound-inch (lbf-in) to Newton-meter (Nm).

Using the formula:

5 × 0.11298483333333333333 = 0.56492416666666666665

Therefore, 5 Pound-inch (lbf-in) is equal to 0.56492416666666666665 Newton-meter (Nm).

How many pound-inches are in one newton-meter? One Newton-meter (Nm) contains 8.8507454540358661708 Pound-inches (lbf-in) — the inverse of the factor above. Multiplying by 0.11298483333333333333 takes you from pound-inches to newton-meters; multiplying by 8.8507454540358661708 brings you back.

Put in words: one pound-inch equals 0.11298483333333333333 newton-meters, so the pound-inch is the smaller unit of this pair. Converting between them never changes the amount of torque being measured — only the size of the unit you count it in.

What Is a Pound-inch (lbf·in)?

A pound-inch (lbf·in) is one pound-force applied at one inch from the axis of rotation. It is the small-torque companion to the pound-foot.

  • 1 lbf·ft = 12 lbf·in (exactly, since a foot is twelve inches)
  • 1 lbf·in = 0.112985 N·m

Why a Smaller Imperial Unit Exists

Many fasteners are tightened to far less than one pound-foot. Writing "0.4 lbf·ft" invites a decimal-point error on a shop floor; writing "5 lbf·in" does not. Small-torque work therefore uses inch units almost exclusively.

Where Pound-inch Is Used

  • Electrical terminals — breaker lugs and terminal blocks are specified in lbf·in, and both under- and overtightening cause failures.
  • Electronics and instrument assembly — small screws in enclosures and connectors.
  • Aerospace fasteners — small-diameter hardware throughout aircraft assembly.
  • Optics, firearms and precision equipment — mounting screws where excess torque distorts the assembly.

Torque screwdrivers and small click wrenches are graduated in lbf·in for exactly this range.

A Common and Expensive Mistake

Confusing lbf·in with lbf·ft applies twelve times the intended torque. On a 5 lbf·in electrical terminal this shears the screw or crushes the conductor. Always check which unit the specification uses before setting a wrench.

Converting Pound-inch

FromToMultiply by
lbf·inN·m0.112985
lbf·inlbf·ft0.0833333
lbf·inozf·in16

What Is a Newton-meter (N·m)?

A newton-meter (N·m) is the SI unit of torque — the twisting force that makes something rotate. One newton-meter is produced when a force of one newton acts at a perpendicular distance of one metre from the axis of rotation.

  • Torque = force × distance, so 1 N·m = 1 N × 1 m

Torque Is Force Times Leverage

The distance matters as much as the force. Pushing on a spanner with 20 N at 0.5 m from the bolt gives 10 N·m. The same 20 N applied through a spanner twice as long gives 20 N·m — identical effort, double the turning effect. This is why a breaker bar loosens a bolt that a short wrench cannot.

The distance is always measured perpendicular to the line of the force. Pulling at an angle reduces the effective lever arm and therefore the torque.

A Newton-meter Is Not a Joule

Both work out to the same base units (kg·m²/s²), but they describe different things and must never be interchanged:

  • A joule is energy — a force acting along a distance.
  • A newton-meter is torque — a force acting at a distance, perpendicular to it.

Standards keep them apart deliberately: energy is written in J, torque in N·m.

Where Newton-meters Are Used

  • Fastener specifications — nearly every modern torque figure is given in N·m.
  • Engines and motors — output torque curves, alongside power in kW.
  • Power tools — cordless drills and impact drivers are rated in N·m.
  • Bicycles — carbon components carry N·m limits because overtightening cracks them.

Quick Reference

TorqueTypical example
5 N·mbicycle stem bolt
25 N·mcar spark plug
110 N·mcar wheel nut
400 N·mfamily car engine peak

Pound-inch to Newton-meter Conversion Table

Here are some quick reference conversions from Pound-inch (lbf-in) to Newton-meter (Nm):

Pound-inchesNewton-meters
0.000001 lbf-in1.1298483333333333333× 10-7 Nm
0.001 lbf-in0.00011298483333333333333 Nm
0.1 lbf-in0.011298483333333333333 Nm
1 lbf-in0.11298483333333333333 Nm
2 lbf-in0.22596966666666666666 Nm
3 lbf-in0.33895449999999999999 Nm
4 lbf-in0.45193933333333333332 Nm
5 lbf-in0.56492416666666666665 Nm
6 lbf-in0.67790899999999999998 Nm
7 lbf-in0.79089383333333333331 Nm
8 lbf-in0.90387866666666666664 Nm
9 lbf-in1.0168635 Nm
10 lbf-in1.1298483333333333333 Nm
20 lbf-in2.2596966666666666666 Nm
30 lbf-in3.3895449999999999999 Nm
40 lbf-in4.5193933333333333332 Nm
50 lbf-in5.6492416666666666665 Nm
100 lbf-in11.298483333333333333 Nm
1000 lbf-in112.98483333333333333 Nm
10000 lbf-in1129.8483333333333333 Nm