Poisson Ratio Calculator
Work out poisson ratio instantly with clear inputs, formula shown and shareable results.
About Poisson Ratio Calculator
Poisson's ratio is the lateral contraction divided by the axial extension, so 180 microstrain of narrowing under 600 microstrain of stretch gives 0.30 - the standard steel value. It caps at 0.5, where the material conserves volume exactly, and rubber sits close to that. The volumetric strain shown is epsilon(1-2nu), which vanishes at 0.5.
Formulas
Poisson's ratio
nu = lateral strain / axial strain
Volume change
volumetric strain = epsilon (1 - 2 nu)
Worked example
With the default values below, Poisson Ratio Calculator returns Poisson's Ratio of 0.3000. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Lateral strain (contraction)minimum 0
- 0.00018
- Axial strain (extension)minimum 0
- 0.0006
Results
- Poisson's Ratio
- 0.3000
- Resulting Volumetric Strain
- 2.4000 × 10⁻⁴
- G/E Ratio Implied
- 0.3846
- Material Class
- Typical engineering metal
Step by step
- 1Values used
- 2Poisson's ratio
- 3Volume change
- 4Poisson's Ratio= 0.3000
- 5Resulting Volumetric Strain= 0.0002
- 6G/E Ratio Implied= 0.3846
- 7Material Class= Typical engineering metal
Assumptions and limits
- The result is derived only from the 2 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
Why can't Poisson's ratio exceed 0.5?
Beyond that the material would gain volume when compressed, which violates energy stability for an isotropic solid.
Do any materials have a negative ratio?
Yes - auxetic foams and some engineered lattices get thicker when stretched. They are rare and deliberately structured.