Voltage Drop Calculator

Estimate the voltage drop along a cable run.

Voltage drop

As current flows through a cable, some voltage is lost to the cable's resistance. The drop is 2 × length × resistance × current (the factor of 2 accounts for the return path). This calculator gives the drop in volts and as a percentage of the source.

Frequently Asked Questions

What is the Voltage Drop Calculator?

Estimate the voltage drop along a cable run. It runs instantly in your browser and is completely free.

Is the Voltage Drop Calculator free and does it require signup?

Yes. Every calculator on Calculatis is 100% free with no registration, and the values you enter are never stored.

How accurate is the Voltage Drop Calculator?

It uses standard, widely-accepted formulas. Results are reliable estimates for general use and are not a substitute for professional advice.