Mechanical & Civil Engineering
Fatigue Endurance Limit (S-N Marin Factors) Calculator
Estimate the corrected endurance limit of a material using Marin surface, size, and load factors.
Your inputs
Change any value to update the result instantly.
Corrected endurance limit
306 MPa
Base endurance limit
400 MPa
Combined Marin factor
0.765
Surface factor ka
0.85
What this calculator does
Fatigue Endurance Limit (S-N Marin Factors) Calculator: Applies the standard mechanics-of-materials relationship for this load case so a student can see how the stress, strain or deflection follows from the geometry and the load.
What your result means
The headline figure tells you how hard the material is being worked, or how much it moves, under the load you entered. Compare it with the allowable value for your material and required factor of safety.
Formula and working
Se = ka·kb·kc·kd·ke·Se'
- 1
Collect the inputs
Base endurance limit Se' = 400 MPa; Surface factor ka = 0.85; Size factor kb = 0.9; Load factor kc = 1; Temperature factor kd = 1
- 2
Apply the formula
Se = ka·kb·kc·kd·ke·Se'
- 3
Result
Corrected endurance limit = 306 MPa
Frequently asked questions
Symbols and assumptions
- Seprime
- Base endurance limit Se' (MPa)
- ka
- Surface factor ka
- kb
- Size factor kb
- kc
- Load factor kc
- kd
- Temperature factor kd
- • The material is homogeneous, isotropic and loaded within its linear-elastic range.
- • Inputs are entered in a consistent unit system, as labelled on each field.
Sources and review
Reviewed 2026-09-22 · Next review 2027-09-22
- • This is an educational estimate for learning and checking, not a design deliverable.
- • Real design must follow the governing code or standard for your jurisdiction and be reviewed and signed off by a qualified engineer.
- • Safety factors, load combinations and material certification are the responsibility of the designer, not of this page.
Important limitation
This is an educational estimate based only on the values and formula shown. Verify current rates, rules, units, and professional standards before relying on the result. It is not personalized financial or investment advice.
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