Enter Calculation Data
Formula Used
Engineering strain: ε = ΔL / L₀
Percentage strain: ε% = (ΔL / L₀) × 100
Elongation: ΔL = εL₀
Final length: L = L₀ + ΔL = L₀(1 + ε)
True strain: εₜ = ln(L / L₀)
Positive strain indicates tension. Negative strain indicates compression.
How to Use This Calculator
- Select the quantity you want to calculate.
- Enter the required lengths or engineering strain.
- Select units independently for each length value.
- Choose decimal or percentage format for entered strain.
- Set precision and scientific notation preferences.
- Press Calculate to view strains, lengths, and solution steps.
- Copy, print, or export the completed calculation.
Example Data
| Original Length | Elongation | Final Length | Engineering Strain | Percentage Strain | True Strain |
|---|---|---|---|---|---|
| 200 mm | 4 mm | 204 mm | 0.02 | 2% | 0.019803 |
| 500 mm | -5 mm | 495 mm | -0.01 | -1% | -0.01005 |
| 10 in | 0.25 in | 10.25 in | 0.025 | 2.5% | 0.024693 |
| 1.2 m | 6 mm | 1.206 m | 0.005 | 0.5% | 0.004988 |
Understanding Elongation and Strain
Elongation measures a specimen’s change in length during loading. Engineering strain divides that change by the original measured length. The resulting value has no physical unit.
Positive elongation usually describes tensile loading and material stretching. Negative elongation represents shortening caused by compressive loading. The calculator identifies both cases from the entered values.
Engineering strain uses the specimen’s original length as reference. This approach is common during small deformation laboratory testing. It remains easy to compare across different specimen sizes.
True strain uses continuously changing length during deformation. Its logarithmic formula becomes useful for larger dimensional changes. Engineering and true strain remain close at small strains.
Length units must describe the same physical dimension. This calculator converts millimeters, centimeters, meters, inches, and feet. Separate selectors prevent manual conversion errors between input values.
Percentage strain presents engineering strain in familiar percent form. A decimal strain of 0.02 equals two percent strain. Compression produces negative values under the standard sign convention.
Material testing often uses strain with stress measurements. Their relationship helps describe stiffness, yielding, and permanent deformation. This calculator handles geometry but does not calculate stress.
Use accurate gauge lengths and measured dimensional changes. Excessive rounding can affect results for very small elongations. Accurate strain calculations support safer designs and clearer decisions.
Frequently Asked Questions
What is engineering strain?
Engineering strain is elongation divided by the specimen’s original length.
Does strain have a unit?
No. Strain is dimensionless because both lengths use equivalent dimensions.
How is percentage strain calculated?
Multiply decimal engineering strain by 100 to obtain percentage strain.
What does negative strain mean?
Negative strain normally means the specimen shortened under compression.
What is true strain?
True strain is the natural logarithm of final length divided by original length.
Can input lengths use different units?
Yes. The calculator converts each selected unit into a common base unit.
Can the calculator solve for elongation?
Yes. Enter original length and engineering strain to calculate elongation.
Why must original length exceed zero?
A zero or negative reference length makes the strain ratio physically invalid.
Is this calculator suitable for large deformation?
It reports true strain for comparison, but advanced testing may require area changes and specialized constitutive models.