Enter your Wire Material, Wire Length, Wire Diameter, and Operating Temperature into the Wire Resistance Calculator to get the Wire Resistance for your chosen conductor, plus Wire Conductance, Cross-Sectional Area, and Resistance per Unit Length — handy when temperature and gauge actually matter for your circuit.
Wire Resistance
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Wire Conductance
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Cross-Sectional Area
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Resistance per Unit Length
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Wire resistance is calculated using the formula R = ρL/A, where ρ is the material's resistivity, L is the wire length, and A is the cross-sectional area. The resistivity depends on the material and temperature.
Wire resistance is directly proportional to length. Doubling the wire length doubles the resistance, as electrons have to travel a longer path through the material, encountering more resistance.
Wire resistance is inversely proportional to cross-sectional area. A larger area provides more paths for current flow, reducing resistance. Doubling the area halves the resistance.
The four main factors are: 1) Material type (resistivity), 2) Wire length, 3) Cross-sectional area, and 4) Temperature. Each factor affects how easily current flows through the conductor.
Resistance measures how much a material opposes current flow (measured in ohms), while conductance measures how easily current flows (measured in siemens). Conductance is the reciprocal of resistance: G = 1/R.
For most metals, resistance increases with temperature because higher temperatures cause more atomic vibrations, creating more obstacles for electron flow. The relationship is typically linear for moderate temperature ranges.
Copper has a resistivity of approximately 1.68×10⁻⁸ Ω·m at 20°C, making it one of the best electrical conductors. This low resistivity is why copper is widely used in electrical wiring.
This calculator provides accurate results for DC resistance using standard resistivity values at the specified temperature. For AC applications at high frequencies, skin effect and other factors may require more complex calculations.