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Engineering Calculators

Safety Factor Calculator

Factor of safety from strength and applied stress, or the allowable load for a chosen factor.

Enter values

Results update as you type.

Result

Safety factor

2.778 ×

Margin of safety
1.778
Utilisation
36%
Assessment
Normal for static structures

About the Safety Factor Calculator

Factor of safety from strength and applied stress, or the allowable load for a chosen factor.

Also known as: factor of safety, fos calculator, design factor, allowable stress.

How to use this calculator

  1. Enter calculate.
  2. The result updates instantly as you type — press Calculate (or Enter) at any time.
  3. Review the breakdown shown under the main result.
  4. Use Copy result or Share to save the answer or send a link with your inputs.

Formula

FoS = material strength ÷ applied stress

Worked example

Using the values pre-filled in the calculator above:

  • Calculate: Safety factor
  • Material strength = 250 MPa
  • Applied stress or load = 90 MPa

the calculator returns:

  • Safety factor: 2.778 ×
  • Margin of safety: 1.778
  • Utilisation: 36%
  • Assessment: Normal for static structures