Torque Calculator — Calculate Moment of Force

Torque (moment of force) is a measure of how much a force tends to rotate an object around an axis. It depends on the force magnitude, arm length and the angle between the force and the arm. The SI unit is the newton-metre (N·m).

Torque is calculated with the formula M = F × r × sin(α), where F is the force in newtons, r is the arm length in metres and α is the angle between the force vector and the arm. Torque is maximum when the force acts perpendicular to the arm (α = 90°).

The moment arm is the perpendicular distance from the axis of rotation to the line of action of the force. The longer the arm, the greater the torque for the same force — which is why a longer wrench makes it easier to tighten bolts.

The SI unit for torque is the newton-metre (N·m). Kilonewton-metres (kN·m = 1000 N·m) are used for large torques, and kilogram-force metres (kgf·m ≈ 9.807 N·m) are a technical unit still seen in older documentation.

Only the force component perpendicular to the arm causes rotation. At 0° or 180° the torque is zero — the force acts along the arm and does not rotate it. Maximum torque is achieved at 90°, where sin(90°) = 1.

Torque calculations are essential in engineering (bolt tightening specifications), automotive (engine torque), construction (beams, levers), biomechanics (muscle and joint forces) and robotics. Every device with a rotational axis requires torque analysis.

Conversion: 1 N·m ≈ 0.1020 kgf·m and 1 kgf·m ≈ 9.807 N·m. The calculator automatically converts the result from N·m to kN·m and kgf·m.

Torsional moment (twisting moment) acts along the axis of an element, causing it to twist — for example a drive shaft. The calculator computes the general moment of force, which can be interpreted as torsional or bending moment depending on the context.

A torque wrench lets you tighten bolts to a specified torque value (e.g. 50 N·m). This prevents thread damage from over-tightening and ensures a safe connection by avoiding under-tightening. Vehicle and machine manufacturers specify recommended torque values in service manuals.

No. The calculator gives an indicative result based on M = F × r × sin(α) and does not constitute engineering advice. Real projects require analysis of dynamic forces, material fatigue, standards and safety factors. A qualified engineer is essential for structural designs.