Voltage Drop Calculator

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Calculate electrical voltage drop based on wire size, distance, current, and conductor type.

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How Voltage Drop Works

Voltage drop occurs when electrical current travels through a conductor and loses voltage due to resistance in the wire. Longer distances and smaller wire sizes increase voltage drop. This calculator helps electricians determine the expected voltage loss and ensure circuits stay within recommended limits.

Voltage Drop Formula

Voltage drop can be calculated using the formula Vd = (2 × K × I × D) ÷ CM for single-phase circuits. In this equation, K represents conductor resistivity, I is the current in amperes, D is the distance in feet, and CM is the circular mil area of the conductor.

Voltage Drop Example

Example: A 120-volt circuit using 12 AWG copper wire carrying 20 amps over 100 feet will experience approximately X volts of drop. This calculator helps electricians quickly determine voltage loss and ensure circuits stay within recommended limits.