Young's modulus
Linear elastic only.
Method
Worked case: 2 mm on 2,000 mm is strain 0.001. At 200 N/mm², E is 200 kN/mm².
What to write beside the result
A review can only check this figure if the inputs sit next to it. Write the value, the unit and the assumption the form used. A diameter in millimetres and a diameter in metres are not the same reading. A force in kilonewtons divided as if it were newtons is a thousand-fold error.
The result is the arithmetic on this page. It is not a utilisation, not a selected product, and not a clause from a standard. If the number is going into a shared container, name the page, the date and the inputs. The file-name checker does not read the calculation.
Logic: how this figure is built.
How to read a modulus
Modulus is stress divided by strain, in the linear range. A 2 mm extension on a 2,000 mm bar is a strain of 0.001. At 200 N/mm² the modulus is 200 kN/mm². That is the slope of the elastic line, not a yield stress.
Strain is extension over original length. The original length is the gauge length, not the whole member, if the extension was measured on a gauge. Mixing those two lengths moves the modulus in proportion.
Past yield the line is not straight. A modulus calculated from a plastic extension is not E. The page does not know whether the test passed yield.
Use it to check a material stamp against a measured pair. It is not a section check.
- Related: direct stress
- structural logic
Last checked 3 October 2026. See the common-calculations note and the disclaimer.