Wire Resistance Tool
Resistance Calculator
Calculate wire resistance based on material, length, and cross-sectional area. Includes temperature correction.
Wire Resistance Calculator
Calculate conductor resistance with temperature correction
How It Works
Resistance Formulas
The physics behind wire resistance calculations.
Basic Resistance
R = ρ × L / A
- R = Resistance (ohms)
- ρ = Resistivity (Ω·mm²/m)
- L = Length (meters)
- A = Cross-sectional area (mm²)
Temperature Correction
RT = R20 × (1 + α × ΔT)
- RT = Resistance at temperature T
- R20 = Resistance at 20°C
- α = Temperature coefficient
- ΔT = Temperature difference from 20°C
Comparison
Material Properties
Resistivity values for common conductor materials.
| Material | Resistivity (Ω·mm²/m) | Temp Coeff (/°C) | Relative to Copper |
|---|---|---|---|
| Copper | 0.01724 | 0.00393 | 100% |
| Aluminum | 0.02826 | 0.00403 | 164% |
| Silver | 0.01587 | 0.0038 | 92% |
| Gold | 0.02214 | 0.0034 | 128% |
| Steel (low carbon) | 0.143 | 0.005 | 829% |
Temperature Effects on Resistance
For metallic conductors, resistance increases with temperature. This is important for high-current applications where conductor heating can significantly increase resistance and power loss.
Practical tip: For critical applications, calculate resistance at the expected operating temperature, not just room temperature. A wire at 75°C can have 20% higher resistance than at 20°C.
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