Enter any three of resistivity ρ, length L, area A and resistance R (use consistent units) to calculate the fourth.
Resistivity law relates resistance to material resistivity, length and cross-sectional area: R = ρL/A.
Resistivity ρ depends on the material, longer conductors have higher resistance, and larger area reduces resistance.
Typical units are ρ(Ω·m), L(m), A(m²), and R(Ω). Units must be consistent.
Temperature changes resistivity; metals usually increase resistance as temperature rises.
The formula assumes a uniform cross-section and homogeneous material for estimation.
Use this calculator for fast learning checks and engineering estimates.
R = ρL/A.
Ohm·meter (Ω·m).
Resistance increases.
Resistance decreases.
Ohm (Ω).
R = ρL/A.
ρ = R A / L.
A = ρL / R.
Inconsistent units lead to incorrect results.
Yes, metals usually increase resistivity with temperature.
Quick conversion between resistivity, length, cross-sectional area and resistance.
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