DC Cable Voltage Drop Calculator
Estimate resistive voltage drop with a manufacturer-provided conductor resistance. This tool is deliberately limited to DC.
DC Cable Voltage Drop Calculator
Calculations run in your browser. Sharing puts numeric assumptions in the link. No registration required.
Formula
Worked example
100 A over a 50 m one-way circuit at 0.5 Ω/km gives 5 V drop, or 10.42% at 48 V.
What this calculation does not cover
Assumes equal outgoing and return conductors; ignores contacts and parallel conductors. Enter resistance at the intended operating temperature. Does not calculate ampacity or AC reactance, and does not certify an allowable drop.
Using the result responsibly
Keep a record of the input units and operating assumptions. A change in one input can make two apparently similar equipment options impossible to compare. Export the scenario before reviewing it with your engineer or equipment manufacturer.