Strain (Engineering, Basic Definition)

The Strain calculator computes the ratio of change in length to original length.

INSTRUCTIONS: Choose units and enter the following:

• (L₀)  This is the initial length.
• (ΔL)  This is the change in length.

Strain (S):  The calculator return the ratio of strain as a real number.  However, this can be automatically converted to percentage via the pull-down menu.

The Math / Science

This Strain equation computes engineering strain from the simplest definition, where Strain is simply a ration of the change in length to the original length.  

The formula for strain is:

        ε = ΔL / L

where:

• ε is strain
• ΔL is the change in elongation.
• L is the original length

Related Calculators

Engineering strain is defined in terms of the change in length of a physical element (`Delta L`)divided by the original length of the physical element (`L_0`).¹

1. ^ Fundamentals of Engineering. 8th edition, 2nd Revision.  National Council of Examiners for Engineering and Surveying (NCEES) - 2001. ISBN 978-1-932613-59-9.  pg 33