Torque Calculator

Created by Kenneth Alambra
Last updated: Jul 09, 2022

This torque calculator will help you calculate the resulting torque that an object subjected to an applied force will experience. This tool can calculate the torque whether the applied force is perpendicular to the direction of the lever arm or at any angle. In this calculator, you will learn:

  • What torque is;
  • What the torque equation is;
  • How to calculate torque; and
  • How to use this torque calculator.

Keep on reading to start learning.

What is torque?

Torque, also known as the moment of force, is an expression of the amount of force needed to make an object rotate on a pivot point. We can meet the amount of torque an object needs to rotate by finding the correct combination of:

  • the amount of force we need to exert;
  • its angle of direction; and
  • its distance from the pivot point.

Pushing a door by its doorknob would require less force than when pushing at its middle portion and even harder when pushing near the hinge (which is the door's pivot point). You may also find it easier to push the door when your force is perpendicular to the door than when the force is at an angle.

In the next section of this text, let us discuss how to calculate torque and what the equation for torque is.

💡 Fun fact: External factors such as friction between objects and the object's weight can affect the torque needed for the object to rotate.

Torque equation and how to calculate torque

Finding how much torque an object needs to rotate is very easy. All you have to do is multiply the force by its distance from the object's pivot point or axis of rotation. The force has to be perpendicular to the lever arm, which is the line that connects the pivot point and the point at which we apply the force. If the force is at an angle, we can use the sine trigonometric function to find the equivalent force when perpendicular to the lever arm. In equation form, we express the torque formula as shown below:

τ=r×F×sin(θ)\tau = r \times F\times \sin(\theta)

where:

  • τ\tau is the torque;
  • rr is the lever arm distance between the pivot point and the point of force application;
  • FF is the force acting on the object; and
  • θ\theta is the angle (in degrees) between the lever arm and the direction of the force.

Typically, it is equal to 90° for an applied force perpendicular to the lever arm. That gives us a shorter torque formula of τ=r×F\tau = r\times F, since sin(90°)=1\sin(90\degree) = 1.

How to use this torque calculator

To use this calculator, all you have to do is:

  1. Enter the lever arm distance (r); and
  2. Input the force (F) present in the system to find the torque.

Our torque calculator also works the other way. So you can also enter a known torque value and either the lever arm distance or the force to find the missing force or lever arm distance, respectively.

If the force acting on the object is at a particular angle, other than the default and typical 90°, you can enter any angle value by using our calculator in its Advanced mode by clicking the button below our tool.

Kenneth Alambra
τ = rFsin(θ)
Distance (r)
ft
Force (F)
lbf
Torque (τ)
ft-lb
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