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Torque Conversion Calculator

Convert torque values between N-m and lb-ft in either direction. Uses the exact SI-to-imperial factor of 0.737562, with the formula and a worked example.

Direction

Result

73.756 lb-ft

100 N·m equals 73.756 lb-ft

Quick Answer

A torque conversion calculator converts between newton-metres (N-m) and pound-feet (lb-ft) using the exact factor 1 N-m = 0.737562 lb-ft. For 100 N-m, the result is 100 × 0.737562 = 73.76 lb-ft. To convert the other direction, 100 lb-ft = 100 ÷ 0.737562 = 135.58 N-m.

What a Torque Conversion Calculator Does and Its Use

A torque conversion calculator switches between the SI unit for torque (newton-metres) and the US customary unit (pound-feet) using a single exact conversion factor. The two directions use reciprocal factors of the same constant. Converting N-m to lb-ft multiplies by 0.737562; converting lb-ft to N-m divides by 0.737562 (or multiplies by 1.355818). The calculator accepts a value in either unit and returns the equivalent in the other.

The Torque Conversion Formula and Its Exact Factor

lb-ft = N-m × 0.737562 N-m = lb-ft × 1.355818

  • N-m to lb-ft: lb-ft = N-m × 0.737562
  • lb-ft to N-m: N-m = lb-ft × 1.355818
  • Exact SI/imperial definition: 1 N-m = 0.737562 lb-ft

Convert Torque With This Calculator in Three Steps

Inputs

  • Direction: select N-m to lb-ft or lb-ft to N-m
  • Value: the torque value to convert, in the selected input unit

Steps

  1. Select the conversion direction (N-m to lb-ft, or lb-ft to N-m).
  2. Enter the torque value in the input unit.
  3. Read the converted torque in the output field.

Torque Conversion Worked Scenario: Five Reference Values

Converting 100 N-m to lb-ft, and 100 lb-ft to N-m.

  1. N-m to lb-ft: 100 × 0.737562 = 73.7562 → 73.76 lb-ft.
  2. lb-ft to N-m: 100 × 1.355818 = 135.5818 → 135.58 N-m.

100 N-m equals 73.76 lb-ft. 100 lb-ft equals 135.58 N-m.

Where Torque Unit Conversion Is Needed in Practice

Use this calculator when reading a torque specification from a European or ISO standard (which uses N-m) and applying it with an imperial torque wrench (which reads in lb-ft), or vice versa. It is also useful when comparing engine or motor specifications between SI and US datasheets, or when recording test results in one unit system for a report written in the other. The conversion is exact; no precision is lost beyond the decimal places shown.

Assumptions

  • The conversion factor 1 N-m = 0.737562 lb-ft is the exact SI-to-US customary relationship.
  • Pound-feet (lb-ft) and foot-pounds (ft-lb) are treated as the same unit of torque in this calculator.
  • The calculator converts torque only; it does not convert units of energy or work, which use the same dimensional unit but different physical meaning.

Limitations

  • Does not convert to or from other torque units such as N-cm, kg-m, or oz-in; scale the result manually if those units are needed.
  • Does not convert power; power requires a speed component (RPM or rad/s) in addition to torque.
  • Does not validate whether a torque value is appropriate for a given fastener or application; that requires knowledge of fastener grade, lubrication, and joint design.

In Practice

When using a torque wrench calibrated in lb-ft to tighten a fastener specified in N-m, use this calculator to get the target lb-ft value before starting. The most common error is multiplying by 1.36 (a rounded approximation) when a tighter tolerance is needed. For critical fasteners such as cylinder head bolts or suspension components, use the full 0.737562 factor rather than a rounded shorthand to stay within the tolerance band.

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Frequently Asked Questions: Torque Conversion Calculator

How many lb-ft is 1 N-m?

One newton-metre equals 0.737562 pound-feet. To convert any N-m value to lb-ft, multiply by 0.737562. For example, 68 N-m × 0.737562 = 50.15 lb-ft, rounded to two decimal places.

How many N-m is 1 lb-ft?

One pound-foot equals 1.355818 newton-metres. To convert any lb-ft value to N-m, multiply by 1.355818. For example, 40 lb-ft × 1.355818 = 54.23 N-m, rounded to two decimal places.

Are lb-ft and ft-lb the same unit?

For torque, lb-ft and ft-lb describe the same physical quantity and are numerically identical. Engineers often prefer lb-ft specifically for torque to distinguish it from the foot-pound as a unit of energy (work = force × distance in the direction of motion). In practice, most manufacturers and service manuals use the terms interchangeably for torque specifications.

Why is the conversion factor not a round number?

The conversion factor is irrational because it derives from the relationship between the metre (defined in SI) and the foot and pound (defined in the US customary system), which are not exact multiples of each other. The exact value follows from the definitions: 1 lb-ft = 1 lb × 1 ft = 0.453592 kg × 0.3048 m × g, where g = 9.80665 m/s². Working through this chain of exact definitions gives 1 lb-ft = 1.355818 N-m.

Can I use this calculator for engine torque specifications?

Yes. Engine torque specifications are commonly given in N-m on European and Asian datasheets and in lb-ft on US datasheets. Enter the specified value in whichever unit your source uses and read the equivalent in the other. For peak torque comparison between engines, the conversion is exact and no precision is lost.

Sources

Last updated: . Reviewed for accuracy against the formula shown above.