Wire Size / Voltage Drop Calculator

Estimate copper-conductor voltage drop for a two-wire circuit. Results update live as you type.

Circuit Resistance
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Voltage Drop
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Percent Drop
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Voltage at Load
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Inputs valid. Results update live as values change.

Engineering estimate only. Verify final values against project criteria, equipment submittals, manufacturer data, measured field conditions, applicable codes, and engineering judgment.

Need help applying this tool to a controls project or commissioning issue? Contact WEBC.