How to Use Torque Calculator
The Torque Calculator requires three inputs:
- Force (F) — Enter the magnitude of the applied force in Newtons. The Torque Calculator uses SI input for precision.
- Lever Arm Length (r) — Enter the perpendicular distance from the pivot to the line of action of the force, in meters.
- Angle (θ) — Enter the angle between the force vector and the lever arm (0°–180°). Use 90° for a force applied perpendicularly — this gives maximum torque in the Torque Calculator.
- Output Unit — Choose N·m, lb·ft, or kgf·m. The Torque Calculator converts automatically.
The Torque Calculator shows the result instantly, along with the equivalent value in N·m for reference.
Formula & Theory — Torque Calculator
The Torque Calculator uses the standard cross-product definition of torque:
τ = F × r × sin(θ)
When the force is perpendicular to the arm (θ = 90°):
τ = F × r
| Symbol | Meaning |
|---|---|
| τ | Torque (N·m) |
| F | Applied force (N) |
| r | Lever arm length (m) |
| θ | Angle between force and arm (degrees) |
The Torque Calculator computes the scalar magnitude of the torque vector. The direction (clockwise or counterclockwise) depends on the sign convention used in your application.
Unit Conversion Reference
| Unit | Relation to N·m |
|---|---|
| N·m | 1 N·m (base) |
| lb·ft | 1 lb·ft = 1.35582 N·m |
| kgf·m | 1 kgf·m = 9.80665 N·m |
Use Cases for Torque Calculator
The Torque Calculator is valuable in many practical contexts:
- Physics education — Solve rotational mechanics problems and verify textbook answers using the Torque Calculator.
- Mechanical design — Size bolts, fasteners, and rotating shafts by computing the required tightening torque.
- Automotive maintenance — Confirm torque specifications for lug nuts and engine components. The Torque Calculator converts between N·m and lb·ft for international specs.
- Structural engineering — Estimate moment forces on beams and cantilever structures.
- Robotics — Choose servo motors with adequate torque by modelling joint loads with the Torque Calculator.