Where:
s 
= 
Electrical Conductivity (MS/m or mS/cm) 
r 
= 
Electrical Resistivity (ohmmeter or mohmscm) 

Resistivity (r) is an intrinsic property of a material relating to the materials resistance to the flow of electrical current. A high resistivity indicates that a material is not a good conductor of electricity. Resistivity is determined by measuring the electrical resistance over some length of material with a constant crosssection. The materials resistivity is the product of the resistance value and the crosssectional area divided by the length as given in the following equation.
where

ρ = resistivity (ohm meters)

R = electrical resistance of a uniform specimen of the material (ohms)

l = length of the specimen (measured in meters)


A = crosssectional area of the specimen (meters
^{2})
Conductivity is calculated by simply taking the inverse of resistivity. A material with a resistivity of 1/58 ohmmeter will have a conductivity of 58 MegaSiemens per meter.