Find the average shear stress on a cross-section from an applied shear force and area, for single or double shear connections, plus the resulting factor of safety against the material's shear strength.
Quick Facts
Direct shear stress
τ = V / A
Average shear stress equals the shear force divided by the area it acts across, parallel to the surface rather than perpendicular to it.
Double shear
τ = V / (2A)
A bolt or pin loaded in double shear splits the force across two shear planes, halving the stress for the same load.
Units
1 MPa = 1 N/mm² = 145.04 psi
Shear stress uses the same units as any other stress; N/mm² and MPa are numerically identical.
Your Results
Calculated
Shear Stress (τ)
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τ = V / A (or V / 2A for double shear)
Shear Stress (psi)
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Converted from MPa for imperial reference
Factor of Safety
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Allowable shear strength ÷ τ
Shear Stress (Pa)
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SI base units, N/m²
Ready
Enter the shear force, area, shear type, and allowable strength, then press Calculate.
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How to use this calculator
Enter the shear force and the cross-sectional area resisting it, choose whether the connection is in single or double shear, and optionally enter the material's allowable shear strength to check a factor of safety. Click Calculate to see the shear stress in MPa, psi, and Pa, plus the resulting safety margin. Click Reset to restore the default values.
Understanding the inputs
Shear force (V) is the load acting parallel to the cross-section — for example, the load on a bolt, pin, rivet, or the punching force on a sheet. Cross-sectional area (A) is the area of the surface that resists that force, such as a bolt's circular cross-section. Shear type reflects how many planes carry the load: a single lap joint carries the full force on one plane, while a double-shear connection (like a pin through a clevis) splits the load across two planes, halving the stress. Allowable shear strength is the material's shear strength limit (often roughly 0.5–0.6 times its tensile yield strength for ductile metals), used only to compute the factor of safety.
Interpreting the results
The highlighted Shear Stress cards show the direct result of τ = V / A (or V / 2A for double shear), in MPa and psi, with a base-SI Pascal value alongside for reference. The Factor of Safety divides the allowable shear strength by the computed stress — a value of 2 or higher indicates a comfortable margin, between 1 and 2 is a reduced margin worth reviewing, and below 1 means the applied stress exceeds the material's shear strength and the connection would be expected to fail.
Frequently Asked Questions
What is shear stress?
Shear stress is the internal force per unit area that acts parallel to a cross-section, unlike normal (tensile or compressive) stress, which acts perpendicular to it. The basic formula is τ = V / A, where V is the shear force and A is the area resisting it. It uses the same units as any other stress, such as MPa, psi, or Pa.
What is the difference between single and double shear?
In single shear, the applied force is resisted across one cross-sectional plane, so τ = V / A. In double shear, the connection has two load-carrying planes, such as a pin through a clevis, so the same force is split evenly between them and the stress is halved: τ = V / (2A).
How do I calculate the factor of safety for shear?
Divide the material's allowable (or yield) shear strength by the calculated shear stress: FoS = allowable shear strength / τ. A factor of safety of 1 means the applied stress exactly equals the material's shear limit; designs typically target a factor of safety well above 1, often 2 or higher, to allow for uncertainty in loads and material properties.
How is shear strength related to tensile strength?
For many ductile metals, shear strength is roughly 0.5 to 0.6 times the tensile yield strength, based on common yield criteria such as Tresca or von Mises. This is only an approximation — actual shear strength should come from material specifications or testing whenever precise values are needed.