How to Calculate Rotational Torque

by Ryan Menezes

Rotational torque measures a force's tendency to rotate an object. To calculate it, you need to know how large the force is and the length between the axis and the point of force application.

Convert force to Newtons (N). To convert pounds to Newtons, multiply by 4.45. For example, if force equals 100 lbs.:

100 * 4.45 = 445 N

100 lbs. of force is equal to 445 Newtons.

Convert length to meters. To convert feet to meters (m), multiply by 0.3. For example, if length equals 2 feet:

2 * 0.3 = 0.6 meters

2 feet of length is equal to 0.6 meters.

Multiply force by length to calculate torque, which is measured in Newton meters (Nm):

445 * 0.6 = 267 Nm


  • If you don't have a calculator handy, enter your formula into your computer's calculator or a Google search bar.

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About the Author

Ryan Menezes is a professional writer and blogger. He has a Bachelor of Science in journalism from Boston University and has written for the American Civil Liberties Union, the marketing firm InSegment and the project management service Assembla. He is also a member of Mensa and the American Parliamentary Debate Association.

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