Calculate wire resistance

Online calculators and formulas for calculating wire resistance

Calculate wire resistance online


On this page, the electrical resistance is calculated from the length and cross-section of a wire. The specific resistance or conductance of the wire material must be known.

Note, the resistance of the specified simple length is calculated. If you want to calculate the total resistance of a two-pole cable, e.g. a loudspeaker cable, you have to multiply the value by 2. Total resistance = forward line + return line.

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.


Wire Resistance Calculator

 What should be calculated?
  Input
Wire Length (m)
Cross-sectional area (mm2)
Wire resistance (Ω)
  Result
Wire resistance
Cross-sectional area
Wire Length
Wire conductance
Decimal places

Legend

\(\displaystyle A \) Cross-sectional area (mm2)

 \(\displaystyle l \)  Wire Length (m)

\(\displaystyle R \) Wire resistance

\(\displaystyle S \) Wire conductance

\(\displaystyle ρ \) Specific resistance

\(\displaystyle σ \) Specific conductance


Wire resistance formulas

Resistance of the wire \(\displaystyle R=\frac{ρ · l}{A}\)   \(\displaystyle =\frac{l}{σ · A}\)
Length of the wire \(\displaystyle l=\frac{R · A}{ρ}\)   \(\displaystyle =R · A · σ \)
Wire cross-sectional area \(\displaystyle A=\frac{l}{R · σ}\)   \(\displaystyle =\frac{l · ρ}{R}\)
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