As discussed above, resistivity (\(\rho\)) is a property of the material. It can be calculated using Equation \ref{eq:resistivity}, where \(R = \frac{V_L}{I}\) is the resistance in \(\Omega\), \(L[\textrm{m}]\) is the length of the material and \(A[\textrm{m}^2]\) is the cross sectional area where the current passes (width\(\cdot\)thickness) in \(m^2\). \[\rho=\frac{V_L/I}{A}{L}\] Therefore, the SI unit of resistivity is \(\Omega \cdot m\).
It’s important to keep in mind that although resistivity is calculated using the dimensions of the resistor, it is independent of the dimensions.