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Free online bolt design calculator according to IS 800 : 2007. This calculator is intended for educational purpose of bolt design calculation.


  1. This bolt design calculator is for educational purpose only and any commercial use should be warranted by the engineer himself/herself. Website claims no responsibility for the same.
  2. This bolt design calculator is for bearing type bolts and for combined bolt design in shear and tension can be found in the menu.
  3. ‘*’ mark indicated required values without which results will not be displayed.
  4. Check our other civil calculators.

Bolt Design Calculator

Embedded OneDrive Excel Workbook Example

Bolt Design Calculations :

Step 1 : Bolt Details

In this the details of the bolts like the nominal diameter, hole diameter, shank area and root area is calculated.

The Grade bolt decides the ultimate stress (fub) and the yield stress (fyb) of the bolt.

The grade of bolt ranges from 4.6 to 10.9 and above.

Step 2 : Connection Details

In this step it should be ascertained whether it is single shear or double shear of bolts. 

Usually a double shear occurs when there are 3 plates connected with the bolt. 

It also needs to be checked whether the shear plane intercepting is passing through the shank of the bolt or the thread of the bolt.

The pitch distance is taken from clause 10.2.2 of IS 800 – 2007.

The edge distance is taken from clause 10.2.4 of IS 800 – 2007.

Step 3 : Connecting members

Connecting members can be plates, rolled sections, packing plates, etc.

The thickness of connecting members is required in the bolt design calculations for calculating the bearing stress of the plate and bearing stress of the bolt.

The ultimate stress of the plate is required in calculation of bearing capacity of the bolts.

When packing plates are used and if thickness is greater than 6mm, it is essential to reduce the shear capacity by a factor (1-0.0125*t) where ‘t’ is thickness of packing plate.

Step 4 : Shear capacity of bolts

Shear capacity of bolts is calculated from clause 10.3.3 of IS 800:2007.

The shear capacity depends on the ultimate stress of the bolts (fub), the number of shear planes through shank and threads, area of shank and area of root of the bolt.

The shear capacity is further factored by a factor of 1.25*1.732 = 2.165.

Step 5 : Bearing capacity of bolts

Bearing failure of plate and bolt
Bearing failure of plate and bolt

Bearing capacity is calculated for bearing failure of bolts or plate whichever is minimum.

The total shear design of bolt is minimum of shear capacity of bolt and bearing capacity of bolt.


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