Poisson's Ratio Calculator
Poisson's ratio from axial and lateral strain of a loaded bar.
INPUTS
mm
mm
mm
mm
RESULTS
Axial strain εa = ΔL/L
3,000 με
Lateral strain εl = ΔD/D
900 με
Poisson's ratio ν = εl/εa
0.3
Volumetric strain εv = εa(1−2ν)
1,200 με
Typical range
Steel ≈ 0.30, aluminium ≈ 0.33, concrete ≈ 0.20, rubber → 0.50
How it works
Pull a bar and it gets thinner: Poisson's ratio ν is the magnitude of lateral strain per unit axial strain. It is bounded by 0.5 (incompressible, like rubber) and links the elastic constants: G = E/2(1+ν). Concrete's low ν (~0.2) versus steel's 0.3 matters in composite sections and confinement problems.
Worked example
A 100 mm steel gauge stretches 0.30 mm (εa = 3000 με) while its 10 mm diameter shrinks 0.009 mm (εl = 900 με): ν = 900/3000 = 0.30 — the textbook value for steel.
Frequently asked questions
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