Torque Calculator

How to Measure Torque with a Luggage Scale

This method might look simple, but it works extremely well and often more accurately than most cheap torque wrenches. Using a luggage scale and a bit of physics, you can get very precise results for just a few bucks.

Advantages

  • Costs less than $15
  • More accurate than many low-end torque wrenches
  • Works at low or high torque values
  • Luggage scales are very precise (often 0.01 kg or 0.1 lb)
  • Works with any wrench or arm length

The Physics Behind It

We use the basic definition of torque:

Torque (Nm) = Force (N) Γ— Arm length (m)

Then convert that to what the scale reads:

Mass (kg) = Torque / (9.81 Γ— Length in meters)

How to Measure

Measure the distance from the center of the bolt or nut to the exact spot where you pull with the luggage scale. Always pull from the same point you measured, small errors matter!

The website also have presets for most of our custom wrenches.

Note: You don't need a torque wrench for most suspension work but for very low torques 4-12Nm, it's highly recommended to not break shafts. This method works great with ourΒ pin wrench or trunnion torque tool. Just follow the calculator and you're good.
Β Open the Torque Calculator

Example

  • Torque = 8 Nm
  • Length = 0.2 m (20 cm)
  • Force = 8 / 0.2 = 40 N
  • Mass = 40 / 9.81 β‰ˆ 4.08 kg