Wire Size & Voltage Drop Calculator

For component connections and circuits, use Electrical Studio. This calculator estimates voltage drop; it does not select protective devices or establish allowable conductor current.

Estimate voltage drop for entered cable lengths and currents, and compare copper wire sizes. Use Electrical Studio to build your component connection diagram.

Planning workflow: Compare copper wire sizes and voltage drop using entered cable lengths, voltage and current. Saved calculations stay separate from your connection diagram.

Planning Inputs

Circuit 1

Circuit name

Nominal circuit voltage (V)

Operating current (A)

Input power (W; optional with amps)

One-way cable length (ft)

Actual source voltage (V; optional)

Target voltage drop (%)

Circuit type

Copper wire to compare

Results

This estimates copper conductor voltage drop using the complete out-and-back cable length. Wire temperature, allowable current, bundling, insulation, terminations and equipment protection still determine the final installation. AC estimates use entered operating current and conductor resistance; they do not model power factor or reactance.

Enter circuit ratings and cable lengths, then calculate.

Reference: Blue Sea Systems: circuit protection and Victron: DC wiring.