Electrical Conductivity Calculator
Calculate electrical conductivity, resistivity, resistance, or conductance of a material or wire using standard formulas.
Electrical conductivity (σ, sigma) measures how easily electric current flows through a material. It is the inverse of electrical resistivity (ρ, rho). These properties are fundamental to electrical engineering, materials science, and physics.
Key relationships:
Resistivity and Conductivity: σ = 1 / ρ
Where:
- σ = conductivity in siemens per meter (S/m)
- ρ = resistivity in ohm-meters (Ω·m)
Resistance of a wire: R = ρ × L / A
Where:
- R = resistance in ohms (Ω)
- L = length of the conductor (meters)
- A = cross-sectional area (m²)
Conductance: G = 1 / R = σ × A / L
Conductivity values of common materials:
| Material | Conductivity σ (S/m) | Category |
|---|---|---|
| Silver | 6.30 × 10⁷ | Best conductor |
| Copper | 5.96 × 10⁷ | Excellent conductor |
| Gold | 4.10 × 10⁷ | Excellent conductor |
| Aluminum | 3.77 × 10⁷ | Good conductor |
| Tungsten | 1.79 × 10⁷ | Moderate conductor |
| Iron | 1.00 × 10⁷ | Moderate conductor |
| Seawater | ~5 | Weak conductor |
| Drinking water | 0.0005–0.05 | Very weak conductor |
| Glass | 10⁻¹² | Insulator |
| Rubber | 10⁻¹⁵ | Insulator |
Why copper is used for electrical wiring: Copper has excellent conductivity (second only to silver), is mechanically strong, solderable, and relatively affordable. Silver conducts better but is far more expensive. Aluminum is used in high-voltage transmission lines where weight matters more than resistance.
Temperature effect: Metal conductivity decreases as temperature rises — their resistance increases with heat. Semiconductors behave oppositely — their conductivity increases with temperature. This is fundamental to how transistors and diodes work.