Bolt Torque Calculator

The SkyCiv Bolt Torque Calculator is a free tool to help determine the correct amount of rotational force needed to tighten a bolt. Torque is a measure of the conversion of linear force to rotational force at a distance from the axis of rotation.

For engineers, torque is important for connections that bolt or clamp two materials or members together. When Torque is applied to a bolt, this force becomes tension in the bolt threads, which in turn applies a clamping force (or load) between the two materials you are bolting together.

Starting SkyCiv Bolt Torque Calculator...

About this Bolt Torque Calculator

How to use the Bolt Preload Torque Calculator?

To get started with this bolt torque calculator you will need a few details handy. The first of these factors is the K Constant which is the factor that considers the frictional characteristics of the bolt and connected components. The bolt diameter is also required. Additionally, the lubrication factor can also be included in this bolt torque calculator. Finally, the torque or clamping force applied to the bolt is required before running the bolt torque calculation.

What Limitations Does this Bolt Torque has a Calculator Have?

The SkyCiv Bolt Torque Calculator has a few limitations that it is important to be aware of when using. The first limitation is that the bolt torque calculation is completed in metric units, however; automatic unit conversion is available. Bolt threading considerations are not included in this calculator. Finally, the formula used in this calculator is an approximation, as it does not take into account the bolt thread pitch (the angle and density of threads). Please also note that the accuracy of most torque wrenches is around +-25%.

What is the Formula for a Bolt Torque Calculation?

The formula used in this calculator is the bolt torque formula. The formula is:


  • K - Nut Factor Constant Dependant on the Bolt Size and Material
  • d - Diameter of Bolt
  • ct - Lubrication Coefficient
  • F - Clamp Torque or Force

Need more Powerful Connection Design Software?

SkyCiv offers a free calculator for steel beam connection design for shear and moment connection design. With the full SkyCiv connection design software, you can access the full range of steel connection types to perform welded and bolted moment connection calculations for a range of engineering standards.

About SkyCiv

SkyCiv offers a wide range of Cloud Structural Analysis and Design Software for engineers. As a constantly evolving tech company, we're committed to innovating and challenging existing workflows to save engineers time in their work processes and designs.

Bolt Torque Calculator FAQs

Why is bolt torque important?

Bolt torque is important to ensure that the correct amount of clamping torque is applied to a bolted joint. By using a bolt torque calculator engineers can make sure that integrity, performance, and tightening of bolted joints remain consistent across multiple connections.

What factors affect bolt torque?

Multiple factors can affect bolt torque including bolt diameter, bolt threading, material properties, and lubrication. By adding these factors to the bolt torque force calculator above you can easily determine the torque on a bolt.

Where can I find bolt torque specifications?

Bolt manufacturers as well as engineering standards often contain torque specifications that can be used alongside this calculator.

Engineering Professional?

If you are an engineering professional, you might benefit more by using our cloud based 3D Structural Analysis Software beyond this calculator. This software includes integrated design modules such as AISC, ACI, AS, Eurocode and CSA.
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