Mechanical & Civil Engineering
Goodman/Soderberg/Gerber Mean Stress Criteria Calculator
Evaluate fatigue safety factor using Goodman, Soderberg, and Gerber mean-stress failure criteria.
Your inputs
Change any value to update the result instantly.
Goodman factor of safety
2
Soderberg factor of safety
1.818
Gerber factor of safety
2.439
Alternating stress
100 MPa
What this calculator does
Goodman/Soderberg/Gerber Mean Stress Criteria 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
Goodman: σa/Se + σm/Su = 1/n
- 1
Collect the inputs
Alternating stress σa = 100 MPa; Mean stress σm = 60 MPa; Endurance limit Se = 250 MPa; Ultimate strength Su = 600 MPa; Yield strength Sy = 400 MPa
- 2
Apply the formula
Goodman: σa/Se + σm/Su = 1/n
- 3
Result
Goodman factor of safety = 2
Frequently asked questions
Symbols and assumptions
- sa
- Alternating stress σa (MPa)
- sm
- Mean stress σm (MPa)
- Se
- Endurance limit Se (MPa)
- Su
- Ultimate strength Su (MPa)
- Sy
- Yield strength Sy (MPa)
- • 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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