The calculator uses a two-point Basquin fit, S = A * N^b.

How should runouts be handled?

Do not include runouts as failure points in this simple fit.

Is the predicted life guaranteed?

No. It is a research and teaching estimate, not a design guarantee.

ToolsConductScience tool

FatigueFree in-browser calculator

Fatigue Life Calculator.

Fit a simple log-log S-N relation and estimate cycles for a target stress amplitude. For materials research, education, and protocol documentation only. Not a certified inspection, compliance, asset-integrity, or final acceptance tool.

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Validated2026-05-24

CitableMethods and citation included

Calculator

Results update in place

Try it out

Load example fatigue life data to see the full workflow

Fatigue Life inputs

Stress point 1

MPa

Cycles point 1

Stress point 2

MPa

Cycles point 2

Target stress

MPa

Results

Predicted cycles

118709 cycles

Basquin slope

-0.1109

Intercept

3.1427

500

300

Target

380

point	stress Mpa	cycles
1	500	10000
2	300	1000000

Review notes

Two-point fatigue fits are rough teaching estimates. Material scatter and runouts are not modeled.

Methods note

Fits log10(stress) against log10(cycles), then solves the Basquin relation at the target stress.

Scope and limitations

For materials research, education, and protocol documentation only. Not a certified inspection, compliance, asset-integrity, or final acceptance tool.

Results are deterministic calculations from the values entered here. Review units, assumptions, and measurement quality before using outputs in reports or protocols.

Method

Uses the tool-specific formulas and assumptions shown in the calculator output.

Validated

Last validated 2026-05-24. Calculations are designed for planning and documentation support; verify procurement decisions against manufacturer specifications or institutional SOPs.

How to cite

How to Cite

Fatigue Life Calculator (1.2.0). ConductScience, Inc. 2026. Available at: https://conductscience.com/tools/fatigue-life-calculator

For materials research, education, and protocol documentation only. Not a certified inspection, compliance, asset-integrity, or final acceptance tool.

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