Online calculators and formulas for calculating wire resistance
On this page the electrical resistance, the length or the Crosssectional area of a wire can be calculated. Two of the three values and the resistivity or conductivity of the material of the wire must be known.
The specific conductance values of the most common cables are
Material
Conductance
Copper 56.0 Silver 62.5 Aluminium 35.0
For a list of other resistivity and conductance values click here.
Calculate wire resistanceif the length and crosssection are known 

\(\displaystyle R=\frac{ρ · l}{A}\) 
\(\displaystyle R=\frac{l}{σ · A}\) 

Calculate the length of the wireif the resistance and cross section area are known 

\(\displaystyle l=\frac{R · A}{ρ}\) 
\(\displaystyle l=R · A · σ \) 

Calculate the wire crosssectionwhen resistance and length are known 

\(\displaystyle A=\frac{l}{R · σ}\) 
\(\displaystyle A=\frac{l · ρ}{R}\) 
\(\displaystyle A \) Crosssection area
\(\displaystyle l \) Length
\(\displaystyle R \) Resistance of the wire
\(\displaystyle S \) Conductivity of the wire
\(\displaystyle ρ \) Specific resistance
\(\displaystyle σ \) Specific conductance