Stress Concentration Factor Calculator

Written by Great Medico

Updated September 25, 2026 •2 min read

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A stress concentration factor result can look precise while still being wrong if one unit or convention is off. Solid-mechanics results are only useful when the geometry, loading convention, and material property match the physical part being modeled. This page keeps the calculation focused so the number is easy to trace back to the values you entered.

What this calculator does

This calculator isolates the relationship between Maximum stress, Nominal stress and stress concentration factor. That makes it easier to see which input is controlling the result and to distinguish the headline quantity from secondary values shown underneath.

How to use it

For a clean calculation, enter Maximum stress, Nominal stress exactly as defined by the labels and their units. Check the headline value, then scan the supporting metrics for a relationship that should obviously increase or decrease with one input; this is a fast way to catch an entry mistake.

How the calculation works

The concentration factor is Kt = σmax/σnominal. It is a dimensionless ratio comparing the local peak stress with the nominal stress entered on the page.

Example

Using the default example on the page (Maximum stress = 200 MPa; Nominal stress = 100 MPa), the calculator returns stress concentration factor of 2. A modest change to one driving input should move the answer in the direction predicted by the equation, which is a useful unit check.

How to interpret the result

Treat the stress concentration factor as the value for the entered ideal geometry, loading state, and material constants. Compare it only with criteria that use the same stress, strain, hardness, or section-property definition and unit system.

Limitations and notes

Material properties can vary with alloy, processing, temperature, loading rate, direction, and test method; geometric idealizations also matter whenever the real part differs from the entered shape. Before trusting the result, confirm Maximum stress, Nominal stress and the associated units. This calculator does not replace component ratings, code requirements, or physical testing when those are required for a real design.