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Bolt Shear Stress Calculator

Work out a bolt's shear stress from the shear force, diameter and single or double shear planes, using τ = V/(n·A).

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How to use this calculator

Enter Values

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Enter your values and press Calculate to see results.

How to use this calculator

  1. Enter the shear force V across the bolt, in kN.
  2. Enter the bolt diameter d in mm.
  3. Set the number of shear planes (1 for single shear, 2 for double), then read the shear stress.

How it works

The Bolt Shear Stress Calculator finds the average shear stress in a bolt loaded across its axis.

τ = V / (n·A), where A = π·d²/4 is the nominal shank area and n is the number of shear planes. Double shear halves the stress because two cross-sections carry the load.

Worked example

20 kN, M16, double shear. A = π×16²/4 = 201 mm². τ = 20,000 ÷ (2 × 201) ≈ 49.7 MPa.

Common mistakes

  • Mixing up units — enter the shear force in kN (the tool converts to N internally).
  • Forgetting double shear: two shear planes halve the stress, so using single shear when there are two planes doubles your result.
  • Ignoring where the shear plane cuts. If it passes through the threads, use the smaller tensile-stress area and check your design code.

Frequently asked questions

Single vs double shear?

Single shear has one cross-section resisting the load; double shear has two (e.g. a bolt through three plates), so each plane carries half the force.

Should I use the thread or shank area?

This tool uses the nominal shank area. If the shear plane passes through the threads, designers use the smaller tensile-stress (thread) area — be conservative and check your code.

Can I use these results for final design?

No. These calculators are for first-pass sizing, checking and learning. They assume ideal supports, static loads and elastic behaviour, and they don't apply load factors, member capacity, buckling or connection checks. Always verify against the relevant design code (e.g. AS 4100, AS 1170, Eurocode) and have a qualified engineer sign off structural work.

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Cite this tool

Zerdly. (2026). Bolt Shear Stress Calculator. Retrieved from https://www.zerdly.com/tools/bolt-shear-stress-calculator/

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