Elastic Elongation Calculator
How much a bar stretches under load, with the resulting strain and stress.
Results
Elongation
0.63492
mm
Strain
0.00031746
Stress
66.667
MPa
What this tool does
Within the elastic range, a bar stretches in proportion to the load, its length and the inverse of its stiffness. Typical Young's modulus values are 210 000 MPa for steel, 70 000 for aluminium and 110 000 for copper; beyond the yield point this formula no longer applies.
Formula
ΔL = F × L ÷ (A × E) , ε = ΔL ÷ L
Variables
| Symbol | Meaning | Unit |
|---|---|---|
f | Force | N |
l | Original length | mm |
a | Area | mm² |
em | Young's modulus | MPa |
dl | Elongation | mm |
st | Strain | — |
sg | Stress | MPa |
Worked example
- Force20,000 N
- Original length2000 mm
- Area300 mm²
- Young's modulus210,000 MPa
- Elongation0.63492 mm
- Strain0.00031746
- Stress66.667 MPa
Limitations
- For work that must comply with a standard or be signed off, check the result against the applicable code and have it reviewed by a qualified engineer.
- The formula assumes ideal conditions: no friction losses, no air resistance and no efficiency losses unless you enter them.