Factor of Safety Calculator

Building deliberate margin into every design

Factor of safety measures the deliberate gap between a material's actual failure point and the stress it will realistically experience in service - engineering design never targets the exact failure threshold, always maintaining a safety margin.

Worked example

For a material with 400 units of ultimate strength under 150 units of actual applied stress:

FoS = 400 / 150 = 2.667 (Within typical acceptable design range)

Required minimum factors of safety vary significantly by governing design code and application - well-understood, predictable loads might require a factor around 1.5-2, while applications with significant uncertainty or severe failure consequences (like pressure vessels or life-safety structures) typically require substantially higher margins.