How this calculator works
Engineering elongation measures extension relative to the original gauge length. Enter a fraction in inverse modes: 0.2 represents 20%. Use the same gauge marks before and after testing. Elongation at break is obtained only when the final length is measured after fracture according to the relevant tensile-test procedure; it is not a universal material constant.
Formula
epsilon = (Lf - L0)/L0; Delta L = epsilon L0; Lf = L0(1 + epsilon).
Worked example
A gauge length increasing from 50 mm to 60 mm has 10 mm extension and 20% elongation. A 200 mm gauge at 5% elongation reaches 210 mm.
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Frequently asked questions
Is elongation the same as strain?
Engineering elongation is engineering axial strain, commonly reported as a percentage.
Can I compare different gauge lengths at fracture?
Use the specified test standard and gauge length. Localized necking makes fracture elongation depend on the gauge arrangement.
Can the result be negative?
Yes. A shorter final length describes compression, provided the final length stays positive.