Use this bolt bearing stress calculator to calculate the compressive bearing stress between a bolt and a connected plate. The calculator uses applied force, bolt diameter, plate thickness, allowable bearing stress and safety factor to estimate utilisation and pass/fail result.
This calculator estimates the average bearing stress in a bolted joint where a bolt presses against the side of a hole in a connected plate or lug.
The calculator provides:
Bearing stress is only one possible bolted joint failure mode. Bolt shear, plate edge shear, tear-out, tensile stress, preload and fatigue may also need to be checked.
Projected bearing area:
Bearing stress:
Design allowable bearing stress:
Utilisation:
| Symbol | Description | Units |
|---|---|---|
| F | Applied force | N |
| d | Bolt diameter | mm |
| t | Plate thickness | mm |
| Ab | Projected bearing area | mm² |
| σc | Bearing compressive stress | N/mm² |
| σallow | Allowable bearing stress | N/mm² |
| SF | Safety factor | - |
Enter the bolted joint details, then click calculate.
| Result | Meaning |
|---|---|
| Projected bearing area | The approximate contact area used for bearing stress, calculated from bolt diameter multiplied by plate thickness. |
| Bearing stress | The average compressive stress between the bolt and the connected plate. |
| Design allowable stress | The allowable bearing stress divided by the selected safety factor. |
| Utilisation | The calculated bearing stress divided by the design allowable stress. A value below 100% passes this simplified check. |
This calculator checks average bearing stress between a bolt and plate. It does not check all possible bolted joint failure modes.
| This Calculator Includes | This Calculator Does Not Include |
|---|---|
| Projected bearing area | Bolt shear stress |
| Average bearing stress | Plate edge shear or tear-out |
| Utilisation against selected allowable bearing stress | Bolt tensile stress |
| Safety factor adjustment | Thread stripping or nut failure |
| Simple plate or lug bearing check | Fatigue, preload, friction-grip behaviour or joint slip |
For bolt shear stress, use the Bolt Shear Stress Calculator.
For plate edge shear, use the Bolt Plate Shear Calculator.
Bolt bearing stress is calculated using the projected area of contact between the bolt and plate. This projected area is commonly taken as the bolt diameter multiplied by the plate thickness.
The bearing stress calculation is useful for checking whether the connected plate, bracket, lug or clevis may be overstressed around the bolt hole.
A complete bolted joint check may also need to consider bolt shear, bolt tension, plate shear-out, edge distance, hole clearance, preload, fatigue and joint slip.
For further bolted joint theory, see the RoyMech reference page: Bolted Joint Design and Calculations.
For the full calculator section, see: Bolted Joint Calculators.
Bolt bearing stress is calculated by dividing the applied force by the projected bearing area between the bolt and plate:
where F is the applied force, d is the bolt diameter and t is the plate thickness.
Bearing stress is the local compressive stress between the side of the bolt and the connected plate or lug.
A bolt may be strong enough in shear, but the connected plate can still fail locally by excessive bearing stress around the bolt hole.
The projected bearing area is commonly calculated as the bolt diameter multiplied by the plate thickness:
No. This calculator checks bearing stress only. Bolt shear stress should be checked separately.
This calculator is intended for preliminary engineering calculations and educational use. Final bolted joint design should be checked against the relevant design standard, bolt grade, plate material, edge distance, fatigue requirements and safety factors.