Torque per Length Converter
Torque per unit length, sometimes called linear torque density or distributed torque, expresses a twisting moment spread along a length. Its SI unit is the newton-meter per meter (N.m/m), which reduces dimensionally to the newton. This converter handles N.m/m, kN.m/m, the customary pound-force-foot per foot, and pound-force-inch per foot, reducing each to N.m/m as a base. The factors use the exact pound-force (4.4482216152605 N), foot (0.3048 m), and inch (0.0254 m).
Torque per length conversion
Base value (N.m/m) = input * factor(from unit)
Output = base value / factor(to unit)
1 kN.m/m = 1,000 N.m/m
1 lbf.ft/ft = 4.4482216152605 N.m/m
1 lbf.in/ft = 4.4482216152605 * 0.0254 / 0.3048 N.m/m
Torque per length combines a moment (force times moment arm) with a distribution length. The pound-force-foot per foot reduces to the pound-force, 4.4482216152605 N.m/m.
Torque per length context
- The SI unit is the newton-meter per meter (N.m/m), a torque spread per unit length.
- Dimensionally this equals the newton, since the meters cancel.
- 1 lbf.ft/ft equals 4.4482216152605 N.m/m, the exact pound-force value.
- 1 lbf.in/ft scales the pound-force by the inch-to-foot ratio (0.0254 / 0.3048).
- Distributed torque arises in shaft and beam loading problems.
Torque per length: frequently asked questions
What is torque per unit length?
It is a twisting moment distributed along a length, such as a continuous torsional load on a shaft. The SI unit is the newton-meter per meter (N.m/m), which has the same dimension as force.
Why does lbf.ft/ft equal a pound-force?
The foot in the torque numerator and the foot in the length denominator cancel, leaving the pound-force, which is exactly 4.4482216152605 newtons. So 1 lbf.ft/ft is 4.4482216152605 N.m/m.
How is lbf.in/ft converted?
Keep the pound-force (4.4482216152605 N), multiply by the inch moment arm (0.0254 m), and divide by the foot distribution length (0.3048 m). The result is about 0.3707 N.m/m.
Is this the same as plain torque?
No. Plain torque is a moment in newton-meters. Torque per length is a moment distributed over a length, in newton-meters per meter, used for continuous or distributed loading.
How do I convert kN.m/m to N.m/m?
Multiply by 1,000, since a kilonewton-meter is 1,000 newton-meters. So 1 kN.m/m equals 1,000 N.m/m.
Official sources
- NIST Special Publication 811: Guide for the Use of the International System of Units.
- BIPM: SI Units.
Reviewed by the CalculatorHub team, edited by James Graham, 17 June 2026. See our methodology.