# What is Dimensional Formula of Poisson’s ratio?

Posted in Dimensional Formulae | Email This Post |Poisson’s Ratio is defined as the ratio of lateral contraction to linear elongation . It can also be defined as the ratio of unit transverse (Lateral) strain to unit longitudinal strain.

Mathematically,

**Poisson’s ratio (σ) = Lateral Strain / longitudinal strain.**

Since we have different form of strain in the above equation and Dimensional Formula of Strain = M^{0}L^{0}T^{0}.

And we know that ratio of dimensionless quantity is Dimensionless.

Therefore, **Poisson’s ratio is Dimensionless** **and has no SI unit.**