Cable Resistance Calculator

Calculate electrical resistance of cables based on material, length, area, and temperature

Cable Resistance Calculator

Compliant with IEC 60228 Standards

Results:

Resistance (Ω): 0.00

Cable Voltage Drop Calculator
Cable Selection Calculator

How to Use the Calculator

Select Material

  1. Choose "Copper" or "Aluminum"
  2. This determines the base resistivity

Enter Cable Dimensions

  1. Input the cable length in meters (m)
  2. Provide the cross-sectional area in square millimeters (mm²)

Specify Temperature

  1. Enter the operating temperature in Celsius (°C)
  2. Default is 20°C, which is the reference temperature for resistivity

Cable Resistance Fundamentals

Resistivity (ρ)

Resistivity is an intrinsic property of a material that quantifies how strongly it resists electrical current. It's a key factor in determining cable resistance.

  • Copper: Low resistivity, excellent conductor.
  • Aluminum: Higher resistivity than copper, but lighter.

Length (L) & Area (A)

  • Length: Resistance is directly proportional to cable length. Longer cables have higher resistance.
  • Area: Resistance is inversely proportional to cross-sectional area. Thicker cables have lower resistance.

Temperature (T)

  • Resistance of most conductors increases with temperature.
  • The temperature coefficient (α) accounts for this change.

Key Formula:

R = ρ * (L / A) * (1 + α * (T - T₀))

Where:

  • R = Resistance (Ω)
  • ρ = Resistivity (Ω·mm²/m)
  • L = Length (m)
  • A = Cross-sectional Area (mm²)
  • α = Temperature Coefficient (/°C)
  • T = Operating Temperature (°C)
  • T₀ = Reference Temperature (20°C)

Calculation Formulas

Cable Resistance:
R = ρ * (L / A) * (1 + α * (T - T₀))

Resistivity (ρ) at 20°C:

Copper: 0.0172 Ω·mm²/m

Aluminum: 0.0282 Ω·mm²/m

Temperature Coefficient (α):

Copper: 0.00393 /°C

Aluminum: 0.00403 /°C

Example Calculation

Copper Cable:

Length: 100 m

Area: 2.5 mm²

Temperature: 50 °C

ρ (Copper) = 0.0172 Ω·mm²/m

α (Copper) = 0.00393 /°C

R = 0.0172 * (100 / 2.5) * (1 + 0.00393 * (50 - 20))

R = 0.0172 * 40 * (1 + 0.00393 * 30)

R = 0.688 * (1 + 0.1179)

R = 0.688 * 1.1179

Resistance = 0.769 Ω

Related Cable & Wire Calculators

Cable Cross-Section Calculator

Determine the required cross-sectional area for your cable.

Try Calculator

Cable Capacitance Calculator

Calculate the capacitance of a cable based on its geometry.

Try Calculator

Cable Copper Weight Calculator

Estimate the weight of copper in a cable for logistics.

Try Calculator