Torque Converter Calculator

The Torque Converter Calculator is the hub page for changing a twisting moment among newton-meters, kilogram-force meters, foot-pounds, and inch-pounds. Instead of focusing on one pair, it lets you select a value, a source unit, and a target unit, then it displays the selected conversion plus a full unit list. That makes it useful for mixed engineering notes, imported machinery, automotive manuals, bicycle work, motor data, and maintenance records where more than one torque convention appears on the same job.

Torque is force times perpendicular lever-arm distance. A longer wrench can create the same torque with less force because the lever arm is longer; a shorter wrench needs more force for the same turning moment. The unit labels capture that multiplication. N·m combines newtons and meters. ft·lbf and in·lbf combine pound-force with feet or inches. kgf·m uses kilogram-force and meters. The converter changes the unit expression of the same torque; it does not choose the correct value for a bolt, clamp, motor, or shaft.

How the units relate

Newton-meters provide the common base. The factors are 1 N·m for N·m, 9.80665 N·m for 1 kgf·m, 1.3558179483314004 N·m for 1 ft·lbf, and 0.1129848290276167 N·m for 1 in·lbf. Equivalently, 1 N·m is 0.7375621492772654 ft·lbf; the shorter 0.7375621493 value is only a rounded display shortcut and is not the arithmetic input. Multiply by the source factor to get N·m, then divide by the target factor.

The default is 10 N·m to ft·lbf. Dividing 10 by 1.3558179483314004 gives 7.375621493… ft·lbf, displayed as 7.376 ft·lbf. The same 10 N·m is 1.020 kgf·m or 88.507 in·lbf after display rounding.

Formula

The general conversion is:

$\text{value in N·m} = \text{input value} \cdot \text{factor of source unit in N·m}$

Then:

$\text{converted value} = \frac{\text{value in N·m}}{\text{factor of target unit in N·m}}$

The factors used by the calculator are:

Worked example from the calculator

With the default settings, the input is 10 N·m and the target is ft·lbf. The source factor is 1, so the base value remains 10 N·m:

$10 \cdot 1 = 10\ \text{N·m}$

The target factor for ft·lbf is 1.3558179483314004:

$\frac{10\ \text{N·m}}{1.3558179483314004} = 7.375621493\ldots\ \text{ft·lbf}$

The displayed primary result is 7.376 ft·lbf. The all-units list uses the same base value:

$\frac{10\ \text{N·m}}{0.1129848290276167} = 88.507457913\ldots\ \text{in·lbf}$

The conversion list rounds that to 88.507 in·lbf. Keep the exact factors through a chained calculation and round only the final value.

Reference table for common torque scales

These examples show common magnitudes and conversion checkpoints. They are not universal fastener specifications.

Unit choice by domain

Automotive work often mixes N·m and ft·lbf. A metric service manual may specify suspension or engine torque in N·m, while a U.S. wrench scale reads ft·lbf. Small automotive covers, interior parts, sensors, and pan bolts may use in·lbf because the values are too low for a large foot-pound wrench. Bicycle and sports equipment frequently use N·m directly, especially near carbon components where clamp force matters. Industrial and imported machinery may still include kgf·m values in older documentation.

For a narrower metric-to-foot-pound workflow, use the Nm to ft-lbs converter. For small metric-to-inch-pound work, use the Nm to in-lbs converter. If the source value is inch-pounds and the target is newton-meters, use the inch-lbs to Nm converter. The inch-pounds to foot-pounds converter is the best page when only the exact 12 to 1 pound-unit relationship is needed.

Pitfalls to avoid

Do not confuse torque with energy. A newton-meter can look like a joule dimensionally, and a foot-pound can appear in energy contexts, but a torque wrench setting is a twisting moment. Do not treat in·lbf and ft·lbf as interchangeable labels. Do not ignore the sign of a torque in engineering math; the calculator accepts negative values because direction can matter. Do not use conversion alone to determine clamping force. Bolt grade, thread pitch, friction, lubrication, washers, joint material, and tightening sequence can change the outcome. Finally, do not round too early. Convert first, then round to the precision your tool and specification can support.

Sources

• NIST, SI units — SI unit context for force, length, and derived units.
• NIST, The NIST Reference on Constants, Units, and Uncertainty: SI units — official reference material for SI unit names and symbols.
• NIST, Special Publication 811: Guide for the Use of the International System of Units — authoritative tables for the exact international foot and avoirdupois pound relationships and the standard acceleration of gravity, from which the ft·lbf, in·lbf, and kgf·m factors are derived.