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Conductor Resistance Formula

A conductor's resistance comes from its material's resistivity, scaled by its length and cross-sectional area. Longer, thinner conductors have more resistance; shorter, thicker ones have less.

Formula

R = (ρ × L) ÷ A

R
Resistance, in ohms
ρ
Resistivity of the conductor material
L
Conductor length, in meters
A
Cross-sectional area, in square millimeters