 The resistance and conductance of a conductor of uniform cross section, therefore, can be computed as

where formula_5 is the length of the conductor, measured in metres (m), "A" is the cross-sectional area of the conductor measured in square metres (m²), σ (sigma) is the electrical conductivity measured in siemens per meter (S·m−1), and ρ (rho) is the electrical resistivity (also called "specific electrical resistance") of the material, measured in ohm-metres (Ω·m).The resistivity and conductivity are proportionality constants, and therefore depend only on the material the wire is made of, not the geometry of the wire.Resistivity and conductivity are reciprocals