Strain Calculator

The Measurement of Deformation

When you apply Stress to any physical object in the universe, it will deform. Even solid titanium will stretch slightly if you pull it hard enough.

Strain ($\varepsilon$) is the engineering term used to measure exactly how much that material deformed.

Strain is a Ratio, Not a Length

If I tell you a metal wire stretched by 1 inch, is that a lot?

• If the original wire was only 2 inches long, stretching it by 1 inch is massive (a 50% increase).
• If the original wire was a 1-mile-long suspension bridge cable, stretching by 1 inch is completely microscopic.

Because raw length is meaningless without context, Strain is calculated as a unitless ratio: the change in length divided by the original starting length.

The Equation

Because both $\Delta L$ and $L_0$ are measured in meters, the units perfectly cancel out. Strain is just a decimal or a percentage.