Enter the minimum stress (GPa) and the maximum stress (GPa) into the Stress Ratio Calculator. The calculator will evaluate and display the Stress Ratio. 

Stress Ratio Formula

The following formula is used to calculate the Stress Ratio. 

STR = MINS / MAXS * 100
  • Where STR is the Stress Ratio (%)
  • MINS is the minimum stress (GPa) 
  • MAXS is the maximum stress (GPa) 

To calculate the stress ratio, divide the minimum stress by the maximum stress.

How to Calculate Stress Ratio?

The following example problems outline how to calculate Stress Ratio.

Example Problem #1:

  1. First, determine the minimum stress (GPa).
    • The minimum stress (GPa) is given as: 400.
  2. Next, determine the maximum stress (GPa).
    • The maximum stress (GPa) is provided as: 850.
  3. Finally, calculate the Stress Ratio using the equation above: 

STR = MINS / MAXS * 100

The values given above are inserted into the equation below and the solution is calculated:

STR = 400 / 850 * 100 = 47.058 (%)


What is the significance of calculating the stress ratio in materials?

The stress ratio is significant in materials science and engineering because it helps in understanding the fatigue behavior of materials under cyclic loading. By calculating the stress ratio, engineers can predict how a material will perform under repeated stress conditions, which is crucial for designing durable and reliable components.

Can the stress ratio be greater than 1?

No, the stress ratio cannot be greater than 1. Since it is calculated as the minimum stress divided by the maximum stress, and the maximum stress is always equal to or greater than the minimum stress, the stress ratio will always be a value between 0 and 1.

How does the stress ratio affect material fatigue life?

The stress ratio affects material fatigue life significantly. A higher stress ratio (closer to 1) indicates that the material is subjected to a smaller range of stress variation, potentially leading to a longer fatigue life. Conversely, a lower stress ratio (closer to 0) suggests a wider range of stress variation, which can accelerate material fatigue and lead to a shorter fatigue life. Understanding the stress ratio allows engineers to make informed decisions about material selection and design for fatigue resistance.