Enter the shear stress (N/m^2), the polar moment of inertia (m^4), and the radius (m) into the calculator to determine the Shaft Torque.

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## Shaft Torque Formula

The following formula is used to calculate the Shaft Torque.

Tshaft = ss * J/r

- Where Tshaft is the Shaft Torque (N-m)
- ss is the shear stress (N/m^2)
- J is the polar moment of inertia (m^4)
- r is the radius (m)

To calculate shaft torque, multiply the shear stress by the polar moment of inertia, then divide by the radius.

## How to Calculate Shaft Torque?

The following example problems outline how to calculate Shaft Torque.

**Example Problem #1**

- First, determine the shear stress (N/m^2). In this example, the shear stress (N/m^2) is determined to be 500 .
- Next, determine the polar moment of inertia (m^4). For this problem, the polar moment of inertia (m^4) is measured to be 30 .
- Next, determine the radius (m). In this case, the radius (m) is found to be 4.
- Finally, calculate the Shaft Torque using the formula above:

Tshaft = ss * J/r

Inserting the values from above and solving yields:

Tshaft = 500 * 30/4 = 3,750 (N-m)

**Example Problem #2**

Using the same method as above, determine the variables required by the formula. For this example problem, these are:

shear stress (N/m^2) = 750

polar moment of inertia (m^4) = 10

radius (m) = 50

Enter these given values into the calculator or above yields:

Tshaft = 750 * 10/50 = 150** **(N-m)