Fatigue Life Calculator
Calculate factor of safety using Goodman, Soderberg, and Gerber criteria with modified endurance limit correction factors
Fatigue Life Calculator
Calculate factor of safety using Goodman, Soderberg, and Gerber criteria with modified endurance limit.
Criteria
≈ 0.5·S_ut (steel)
Marin Correction Factors
Machined: 0.76–0.9
d<8mm: 1.0
Bending: 1.0
≤70°C: 1.0
99%: 0.814
Modified Endurance Limit
S_e = 229.50 MPa
= 0.9 × 0.85 × 1 × 1 × 1 × 300 MPa
Factors of Safety
Goodman n
1.284
Soderberg n (conservative)
1.219
Gerber n (least conservative)
1.478
Langer (yield) n_y
2.400
Governing Criterion
Soderberg ≤ Goodman ≤ Gerber (most to least conservative)
Goodman: most widely used in practice.
k_a Surface Finish Factor (ka ≈ a·S_ut^b)
How to Use This Calculator
Enter your input values
Fill in all required input fields for the Fatigue Life Calculator. Most fields include unit selectors so you can work in your preferred unit system.
Review your inputs
Double-check that all values are correct and that you have selected the right units for each field. Incorrect units are the most common source of calculation errors.
Read the results
The Fatigue Life Calculator instantly computes the output and displays results with units. All calculations happen in your browser — no loading time and no data sent to a server.
Formula Reference
Fatigue Life Calculator Formula
See calculator inputs for the governing equation
Variables: All variables and their units are labeled in the calculator interface above.
When to Use This Calculator
- •Use the Fatigue Life Calculator when solving homework or exam problems that require quick numerical verification of your hand calculations.
- •Use it during the design phase to rapidly iterate on parameters before running detailed finite element simulations.
- •Use it when reviewing a colleague's calculation or checking a vendor's data sheet for plausibility.
- •Use it to generate reference data for a technical report or presentation without manual computation.
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