Voltage Drop Calculator

Calculate voltage drop, percent voltage drop, final load voltage, and total circuit resistance for automation and electrical circuits using wire gauge, length, current, and conductor material.

Good starting use case: use this for first-pass voltage-drop checks on 24VDC controls, PLC panels, sensors, actuators, solenoids, and machine wiring before you get into code review, thermal ampacity, startup current, and detailed power distribution design.

Estimate Circuit Voltage Drop

Calculate voltage drop, percent voltage drop, and final load voltage for automation and electrical circuits using wire gauge, length, current, and conductor material.

This calculator is useful for 24VDC controls, PLC panels, sensors, actuators, solenoids, and industrial automation wiring where excessive voltage drop can cause poor performance.

Voltage Drop = Current × Circuit Resistance

Total Circuit Resistance = Resistance per Length × Round-Trip Length
Enter values and press Calculate.

Need help applying this to a real machine?

Get connected with a qualified automation integrator if you need help with controls power distribution, panel design, wire sizing, or troubleshooting voltage loss in a real system.

Find an Integrator

This calculator assumes a simple two-conductor circuit using the selected conductor material and AWG size. It is intended for practical estimating, not as a substitute for code review, thermal ampacity checks, or full engineered power distribution design.

In real machine wiring, startup current, shared commons, connector resistance, terminal quality, supply sag, and distributed loads can all make real voltage at the device worse than the simple calculation suggests.

What to check next

This tool is excellent for a fast first-pass check, but real voltage problems often come from more than wire length alone. Connector quality, terminal looseness, undersized commons, power supply sag, shared return paths, and peak inrush loads can all create lower real device voltage than expected.

For real controls design, this page usually works best alongside wire sizing, current review, and actual device voltage requirements so you can confirm the circuit will perform correctly under the real load conditions.