Pound-feet to Newton metres Calculator

Direct answer

Multiply the entered pound-feet value by 1.3558179483314 to express it in newton metres (N·m). This converts pound-foot (lbf·ft) to newton metre (N·m) within the documented torque family.

Variables and formula

• Pound-feet (lbf·ft): the source value measured in pound-foot.
• Newton metres (N·m): the same quantity expressed in newton metre.
• Conversion factor: 1.3558179483314 newton metres per pound-foot.

Newton metres = Pound-feet × 1.3558179483314

The generator emits numeric factors with at most 15 significant digits. Calculator results keep up to 10 significant digits for display; this formatting does not increase the precision of the measurement.

Unit definitions and named variants

Source unit: pound-foot (lbf·ft). This torque unit is one pound-force acting at a perpendicular distance of one international foot; the qualified unit is lbf·ft. Named variant used: Pound-force foot using the international foot; not pound mass foot or energy terminology. Reference: National Institute of Standards and Technology: NIST Guide to the SI, Appendix B.9: Factors for Units Listed by Kind of Quantity or Field of Science; National Institute of Standards and Technology: NIST Guide to the SI, Footnotes; National Institute of Standards and Technology: NIST Handbook 44 (2026), Appendix C: General Tables of Units of Measurement.

Target unit: newton metre (N·m). The newton metre is the coherent SI expression used for torque: force in newtons multiplied by perpendicular lever arm in metres. Named variant used: Torque, not energy. Reference: Bureau International des Poids et Mesures: The International System of Units (SI), 9th edition, version 4.01.

The lbf·ft-to-N·m direction remains inside the torque quantity; it changes the unit label and numerical scale, not the kind of quantity being measured.

Relationship and precision

The named unit relationships are defined or exact, so the conversion is exact before display rounding and source-measurement uncertainty.

• lbf·ft relationship: The raw exact product is 4.4482216152605 N × 0.3048 m = 1.3558179483314003 N·m; the generator emits the route factor once at 15 significant digits.
• N·m relationship: The base factor is exactly 1 by the family base-unit choice.

To audit the factor through the family base unit, divide the raw dataset factors 1.3558179483314003 by 1. The generator emits that quotient once at 15 significant digits as the canonical direct factor 1.3558179483314; runtime calculations do not divide the already-emitted base factors again.

Reproducible example

For 10 pound-feet, 10 × 1.3558179483314 = 13.558179483314 newton metres. Repeating the same multiplication with the stated factor reproduces the displayed conversion before interface rounding.

Directional scale check

Because one pound-foot contains 1.3558179483314 newton metres, the target number is larger than the source number for every positive input. Zero maps to zero, while negative inputs are preserved as signed values under the stated direction convention.

Interpretation

Read the result as newton metres, not pound-feet. A value entered as lbf·ft leaves the calculator labelled N·m; this directional distinction matters even when the two units describe the same torque quantity.

Assumptions and limitations

• A negative value denotes torque opposite the chosen positive rotational direction.
• Torque and energy share dimensions, but BIPM specifies newton metre for torque and states that joule must not be used for it.
• The pound-foot and pound-inch slugs preserve established route names for pound-force foot and pound-force inch. The UI uses qualified symbols lbf·ft and lbf·in; lb·ft and lb·in remain ambiguous search aliases only.

Common mistakes

• The UI uses the force-qualified symbol lbf·ft; lb·ft is retained only as an ambiguous search alias.
• N·m uses a multiplication dot; nm means nanometre.

Continue within the Torque family

See the Torque conversion hub for its five-unit reference table and all 20 directed routes.

• Reverse the direction: Newton metres to Pound-feet
• Compare another torque route: Pound-feet to Kilonewton metres
• Compare another torque route: Pound-feet to Pound-inches
• Compare another torque route: Pound-feet to Kilogram-force metres
• Compare another torque route: Newton metres to Kilonewton metres

Assumptions

• The entered value uses pound-feet exactly as labelled.
• A negative value denotes torque opposite the chosen positive rotational direction.
• Rounding and measurement uncertainty remain the user's responsibility.

Sources and methodology

CalcMotive publishes the formula and assumptions so you can decide whether the estimate fits your use case. See our methodology standards.

• The International System of Units (SI), 9th edition, version 4.01; Bureau International des Poids et Mesures; accessed Aug 7, 2026
• NIST Guide to the SI, Appendix B.9: Factors for Units Listed by Kind of Quantity or Field of Science; National Institute of Standards and Technology; accessed Aug 7, 2026
• NIST Guide to the SI, Footnotes; National Institute of Standards and Technology; accessed Aug 7, 2026
• NIST Handbook 44 (2026), Appendix C: General Tables of Units of Measurement; National Institute of Standards and Technology; accessed Aug 7, 2026