A Voltage drop calculator is a invaluable when wiring battery chargers, electrical accessories, driving lights, auxiliary batteries etc, particularly when dealing with long cable runs or high-load accessories. Use the calculators below to check voltage drop, so you can choose the correct cable size.

The 'voltage drop' result will dynamically re-calculate as the length, load and wire size fields are modified. The calculators below assume copper wire at 25ºC. Voltage drop increases slightly with temperature.

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