Voltage Drop Calculator

Use an AWG geometry and resistivity estimate to calculate round-trip wire resistance and voltage drop.

System voltage (V)

Current (A)

One-way length

Length unit

Wire gauge (AWG)

Material

Path

—Voltage drop

—Drop percent

—Load voltage

—Estimated path resistance

Estimate at roughly 20°C using AWG diameter geometry and conductor resistivity. Real installations vary with temperature, connections, conductor construction, code requirements, and AC effects.

How to use this Voltage Drop Calculator

Estimate conductor voltage drop from current, wire gauge, material, and one-way length. Enter your values above and the result is calculated directly in your browser. No account is required.

Fast answer, clear inputs

This tool is built around one job: give the answer quickly without forcing a signup or hiding the result. Related tools are linked nearby when the next calculation or conversion is useful.