Free Factor of Safety Calculator
Calculate the factor of safety by comparing material strength to applied stress or ultimate load to working load.
MPa
MPa
Factor of Safety
1.67
Utilization Ratio60.0 %
Factor of Safety vs Material Strength / Ultimate Load
Factor of Safety (FoS)
The factor of safety expresses how much stronger a system is than it needs to be.
Formula
FoS = Strength / Applied Load
A FoS of 1.0 means the member is at its exact limit. Values above 1.0 provide a safety margin. Typical minimum factors: buildings 1.5-2.0, bridges 2.0-3.0, aircraft 1.25-1.5, pressure vessels 3.0-4.0.
Example Calculation
A steel member with 250 MPa yield strength under 150 MPa stress.
- 01FoS = 250 / 150 = 1.67
- 02Utilization = 150 / 250 = 60%
- 03The member has a 67% safety margin above the working load.
Frequently Asked Questions
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