Online Tools

    Wire Resistance Calculator

    Calculate wire resistance from material, length, cross-sectional area and temperature, with optional voltage-drop estimates.

    If you know the conductor diameter, convert it to cross-sectional area first. For a round conductor, use the circle area.

    Resistance from resistivity

    English search intent for this model is wire resistance: resistance from material resistivity, length and cross-sectional area.

    R is resistance, rho resistivity, L conductor length and A cross-sectional area.

    Longer conductors have higher resistance; larger cross-sections have lower resistance.

    Voltage-drop estimate

    Code and safety limits
    Voltage drop and ampacity depend on installation method, insulation, temperature, conductor material and local electrical code.

    Frequently Asked Questions

    Sources and References

    Calculations are based on the listed reference sources. Links open in a new tab.

    Updated:

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