Physics

Torque Calculator

Calculate torque from force, lever arm, and angle so you can estimate rotational force for mechanics, engineering, and physics problems.

Free No sign-up Instant results

Torque Calculator

A torque calculator helps you estimate rotational force from the force applied, the lever arm length, and the angle between them. Students, mechanics, and engineers use a torque calculator when they want a fast answer for a physics problem, a tool setup, or a real-world task such as understanding how strongly a force will turn a shaft, wheel, or wrench.

The important idea is that torque is not only about how hard you push. It also depends on how far from the pivot you apply the force and whether the force acts at the most effective angle. That is why the same force can create very different turning effects.

How to Use the Torque Calculator

  1. Enter the applied force in newtons or the unit shown in the calculator.
  2. Enter the lever arm length, which is the distance from the pivot point to where the force is applied.
  3. Enter the angle between the force direction and the lever arm.
  4. Review the torque result in newton-metres or the output unit provided.
  5. Use the result to compare setups, solve a physics problem, or estimate whether a longer lever arm changes the turning effect enough to matter.

If the force is applied at a right angle to the lever arm, the torque is at its maximum for that force and distance.

What the Torque Calculator Measures

The torque calculator measures the turning effect created when a force acts on an object around a pivot or axis.

InputWhat it meansExample
ForceAmount of push or pull applied50 N
Lever armDistance from pivot to point of force0.30 m
AngleAngle between force and lever arm90°
Output torqueRotational effect produced15 N·m

This is useful because it shows why position and angle matter just as much as force in many mechanical systems.

Torque Formula

The standard formula is:

Torque (tau) = Force x Lever arm x sin(angle)

In symbols, that is often written as:

tau = F x r x sin(theta)

When the angle is 90°, the sine term becomes 1, so the torque simplifies to force multiplied by lever arm. When the force acts in line with the lever arm, the turning effect is much smaller because the sine term drops toward zero.

Example Torque Calculation

Suppose a force of 50 N is applied to a wrench at a distance of 0.30 m from the pivot, and the force is applied at 90°.

The calculation is:

Torque = 50 x 0.30 x sin(90°)
Torque = 50 x 0.30 x 1
Torque = 15 N·m

Now compare that with applying the same force at 30° instead of 90°.

Torque = 50 x 0.30 x sin(30°)
Torque = 50 x 0.30 x 0.5
Torque = 7.5 N·m

That example shows why the angle matters. The same force and lever arm can produce only half the torque when the direction of force is less effective.

What Changes Torque Most

Applied force

A larger push or pull increases torque directly if the lever arm and angle stay the same.

Lever arm length

A longer wrench, handle, or radius increases torque because the same force acts farther from the pivot.

Force angle

Torque is strongest when the force acts close to perpendicular to the lever arm. As the angle gets smaller, less of the force contributes to rotation.

How to Interpret Torque Results

  • Use the result to compare turning effect, not just raw force.
  • Check that your force, distance, and angle units match the calculator inputs.
  • Remember that friction, slipping, or tool losses can affect a real-world setup even if the pure torque math is correct.
  • Use a perpendicular force assumption only when the setup actually supports it.

If you are using torque in a vehicle or applied-mechanics context, it can help to compare this result with a Horsepower Calculator, Power-to-Weight Ratio Calculator, 0-60 Estimate Calculator, or Tire Size Calculator.

Common Torque Mistakes

  • Forgetting the angle term and multiplying force by lever arm in every case.
  • Mixing centimetres and metres or pounds-force and newtons without converting.
  • Measuring the wrong lever arm distance from the pivot.
  • Assuming more force always helps even when the angle is poor.
  • Treating theoretical torque as the only factor in a real mechanical system.

FAQ

What is torque?

Torque is the turning effect created when a force acts at a distance from a pivot or axis.

Why does angle matter in torque?

Only the force component acting perpendicular to the lever arm creates the full turning effect, which is why the sine of the angle appears in the formula.

What is the unit of torque?

Torque is commonly measured in newton-metres, written as N·m, in metric calculations.

Is torque the same as force?

No. Force is a push or pull, while torque describes how strongly that force tends to rotate something around a pivot.

When is torque highest?

For a given force and lever arm, torque is highest when the force is applied at 90° to the lever arm.