Wire Size & Voltage Drop Calculator

Liguori Drag Racing • Electrical

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Wire Size & Voltage Drop

Compare copper wire gauges for a chosen DC voltage-drop limit.

Starting values are examples. Enter your measurements; results update as you type.

Method & assumptions

Voltage-drop comparison only. Assumes equal copper supply and return conductors, 100% IACS copper at 20°C, and 0.00393/°C resistance coefficient. Connector, relay, and chassis-ground losses are excluded. The displayed gauge is not an ampacity or fuse recommendation: confirm wire insulation, bundling, installation temperature, current rating, and circuit protection with the wire manufacturer.