Wire Resistance Calculator
Calculate wire resistance from material and dimensions.
This tool is for informational and educational purposes only. It is not a substitute for professional financial, medical, legal, or engineering advice. See Terms of Service.
Can't find what you need?
Request a ToolHow to Use the Wire Resistance Calculator
Enter the material resistivity, wire length, and cross-sectional area. Common resistivities: copper 1.68e-8, aluminum 2.65e-8, steel 1.43e-7 ohm m. The calculator shows total and per-meter resistance.
About Wire Resistance
Wire resistance depends on three factors: the material (resistivity), length, and cross-sectional area. The formula R = rho L / A (where rho is resistivity) is fundamental in electrical engineering. Copper is preferred for wiring due to its low resistivity. Longer wires and thinner gauges have higher resistance, causing more voltage drop and heat generation. Proper wire sizing is essential for electrical efficiency and safety.
Frequently Asked Questions
What is resistivity?
Resistivity is a material property that quantifies how strongly a material opposes current flow. Copper has a resistivity of about 1.68 x 10^-8 ohm m. Lower resistivity means better conductivity.
How does wire length affect resistance?
Resistance is directly proportional to length. Doubling the wire length doubles the resistance, all else being equal.
How does cross-sectional area affect resistance?
Resistance is inversely proportional to area. Thicker wires have lower resistance because current has more room to flow, similar to water flowing through a wider pipe.