Electrical Conductivity Calculator
Calculate electrical conductivity, resistivity, resistance, or conductance from material properties and wire dimensions using standard electrical 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.
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