Calculate the turning effect of a force with τ = F · r · sinθ — enter force, lever-arm length and the angle, or solve for force or radius. Torque is measured in newton-metres.
Torque is the rotational equivalent of force — the twisting effect that makes something rotate about a pivot. It is τ = F r sinθ, where F is the force, r the distance from the pivot (lever arm) and θ the angle between them.
Torque is greatest when the force is applied perpendicular to the lever arm (θ = 90°, sinθ = 1) and at the greatest distance from the pivot — which is why a longer wrench loosens a bolt more easily. The unit is the newton-metre (N·m).
Torque is τ = F r sinθ — force times the lever-arm length times the sine of the angle between them. When the force is perpendicular (θ = 90°), it simplifies to τ = F r.
For a force applied at right angles to the lever arm, τ = F × r — force times distance from the pivot. The full form τ = F r sinθ handles other angles.
The newton-metre (N·m). Although dimensionally the same as the joule, torque is kept as N·m to distinguish it from energy.
Because torque increases with the lever-arm length r. A longer wrench means a larger r, so the same force produces more torque and turns the bolt more easily.