Formula used

The standard relationship between newton-meters and foot-pounds force is fixed. One newton-meter equals approximately 0.7375621493 foot-pounds force.

The calculator converts every supported unit through newton-meters. This method keeps the conversion chain consistent and avoids accumulating unnecessary rounding errors.

How to use this calculator

1. Enter the torque value you need to convert.
2. Select the source torque unit.
3. Select the required target torque unit.
4. Choose decimal places, significant figures, and a rounding method.
5. Use the live result for a quick answer.
6. Press the main button for a server-verified result.
7. Copy, print, favorite, or export the completed conversion.

Use the batch tab when several values need the same conversion. Use the torque-from-force tab when force, lever length, and angle are known instead of torque.

Supported torque units

Worked conversion examples

Example 1: Convert 100 N·m to ft·lbf

Multiply 100 by 0.7375621492772656. The unrounded answer is 73.75621492772656 ft·lbf. A practical display using four decimals is 73.7562 ft·lbf.

Example 2: Convert 50 ft·lbf to N·m

Multiply 50 by 1.3558179483314004. The result is about 67.79089741657 N·m. The displayed value depends on the chosen precision settings.

Example 3: Calculate torque from force

A 100 N force acts at 90 degrees on a 0.5 m lever. Torque equals 0.5 × 100 × sin(90°). The resulting torque is 50 N·m.

Example 4: Convert a negative value

A value of −25 N·m converts to about −18.4391 ft·lbf. The negative sign commonly identifies the opposite rotational direction under an established sign convention.

Understanding torque and torque units

Torque describes the turning effect produced when force acts at a distance from a pivot. The effect depends on the applied force, the perpendicular lever arm, and the angle between the force direction and the lever.

The general relationship is τ = rF sin(θ). Torque reaches its maximum magnitude when the force acts at 90 degrees. A force aimed directly toward the pivot produces no turning effect because the perpendicular component is zero.

Newton-meter is the standard SI torque unit. Foot-pound force is widely used in imperial engineering and automotive service information. Although energy can also be expressed using newton-meters, torque and energy describe different physical ideas. Context determines the intended quantity.

Lowercase “nm” normally represents nanometer, a length unit. Torque should be written as N·m, with a capital N and a multiplication dot. The calculator accepts the common typed form but displays the correct torque notation.

A torque wrench may show N·m, ft·lbf, in·lbf, or several scales. Always use the same unit stated by the equipment manufacturer. Conversions should preserve enough precision for the available wrench scale without suggesting unrealistic accuracy.

Accuracy, rounding, and practical use

The conversion factors in this calculator use a high-precision relationship derived from exact SI definitions. Internal calculations keep floating-point precision until the final formatting stage.

Decimal-place rounding controls the number of digits after the decimal separator. Significant figures control the overall meaningful digit count. When significant figures are enabled, they override the decimal-place setting.

Normal rounding is appropriate for most work. Upward and downward rounding are directional. Truncation simply removes extra displayed digits. These methods can produce different results, especially around negative values.

A displayed result is not automatically a safe tightening specification. Bolt torque depends on material, thread condition, lubrication, fastener grade, joint design, temperature, and manufacturer instructions. Use the calculator only to convert an authoritative specification.

Reference examples on this page are educational. They are not universal values for wheels, engines, bicycles, structures, or pressure equipment. Confirm every critical torque with the service manual, drawing, or responsible engineer.

Common conversion mistakes

• Multiplying by 1.3558 when converting from N·m to ft·lbf.
• Using in·lbf when the specification requires ft·lbf.
• Confusing mass units with force units.
• Entering a comma decimal under dot-decimal settings.
• Rounding too early during a chain of calculations.
• Reading “nm” as torque without checking the context.
• Assuming a converted reference value is a tightening recommendation.
• Ignoring the sign convention for clockwise and counterclockwise torque.

Engineering notes for advanced users

Torque is an axial vector. Its direction follows the right-hand rule. A scalar conversion keeps the numeric magnitude and sign but does not independently model three-dimensional direction.

For vector calculations, torque is the cross product of position and force. The scalar formula used here is the magnitude of that relationship when the angle between both vectors is known.

Static tightening torque does not directly equal bolt preload. Friction consumes a large portion of tightening torque. More controlled fastening methods may use torque-angle, hydraulic tensioning, ultrasonic elongation, or direct tension indicators.

Dynamic torque measurements may require sampling rate, transducer calibration, zero correction, filtering, and uncertainty analysis. This page performs deterministic unit conversion and elementary moment calculations. It does not replace calibrated measurement systems.

Frequently asked questions