Torque from force
Force at right angles to the arm.
Method
T = Fr. Worked case: 500 N at 0.25 m is 125 N·m.
What to write beside the result
A review can only check this figure if the inputs sit next to it. Write the value, the unit and the assumption the form used. A diameter in millimetres and a diameter in metres are not the same reading. A force in kilonewtons divided as if it were newtons is a thousand-fold error.
The result is the arithmetic on this page. It is not a utilisation, not a selected product, and not a clause from a standard. If the number is going into a shared container, name the page, the date and the inputs. The file-name checker does not read the calculation.
Logic: how this figure is built.
How to read a torque
This page answers T = Fr for a force at a right angle to a radius. A 500 N force at 0.25 m is 125 N·m. It is the moment of that force about the centre you named. It is not a shaft design and not a bolt preload.
The radius is the perpendicular distance from the line of action to the centre. If the force is not tangential, the perpendicular component is the one that produces torque. Using the full force when it is angled overstates the moment.
Unit consistency is the usual failure. A force in kilonewtons and a radius in millimetres is not a newton-metre until you convert. 125 N·m is 0.125 kN·m. A drawing in millimetres needs that conversion written down before the number is compared with a motor torque.
Use it to check a lever, a winch radius or a hand calculation beside a model. Shaft power needs speed as well as torque. This page does not have a speed. It also does not apply a factor of safety.
- Related: shaft power
- mechanical guide
Last checked 3 October 2026. See the disclaimer.