How this calculator works
Torque measures a force's turning effect about an axis. Only the component perpendicular to the radius contributes. Enter the actual distance to the point of application and the angle between that radius vector and the force. Results are magnitudes; clockwise or counterclockwise direction requires the force geometry and the right-hand rule. Inverse angle mode reports the acute principal solution.
Formula
tau = r F sin(theta); F = tau/[r sin(theta)]; theta_principal = asin(tau/(rF)).
Worked example
A 10 N force perpendicular to a 2 m lever arm produces 20 N m. A 5 N m torque at radius 1 m and angle 30 degrees requires 10 N.
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Frequently asked questions
Why does a parallel force give zero torque?
Its line of action has zero perpendicular distance from the axis.
Is torque measured in joules?
Although both involve force times distance, torque is expressed in N m to distinguish turning effect from energy.
Can another angle give the same torque?
Yes. An acute angle and its supplementary obtuse angle have the same sine and torque magnitude.