# DC Cable Voltage Drop Calculator

Estimate resistive DC drop in a two conductor circuit from an entered conductor area.

[Open this tool](https://whatson.pk/voltage-drop-calculator/)

Category: Solar & Battery

DC voltage drop depends on conductor resistance across the full outgoing and return path.

Enter current, conductor area and one way distance. Compare the estimated drop and loss before seeking the separate cable and protection checks.

## Inputs and controls

* DC source voltage (V). Allowed range: 0.01 to 2000
* Current (A). Allowed range: 0 to 1000000
* One way cable length (m). Allowed range: 0 to 10000
* Conductor cross section (mm²). Allowed range: 0.01 to 10000
* Resistivity at entered condition (Ω mm²/m). Allowed range: 1.0E-5 to 1. Default is an illustrative copper approximation; adjust for material and temperature.

## How to use

* Enter DC source voltage, current and one way cable length.

* Enter conductor cross section and resistivity at entered condition.

* Select Calculate result. Read the returned values alongside the assumptions below before copying, exporting or acting on the result.


## Why use this tool

The loop length basis helps avoid calculating resistance for only half of a two conductor circuit.


## Before relying on the result

Loop length is twice the one way distance. This is resistance arithmetic only, not cable ampacity, breaker selection or an installation recommendation. Connections and circuit topology can add losses.


## Tool limitations

Loop length is twice the one way distance. This is resistance arithmetic only, not cable ampacity, breaker selection or an installation recommendation. Connections and circuit topology can add losses.

## Questions

### Does this choose a safe cable size?

No. Ampacity, installation conditions, connections and protection requirements need separate assessment.

### What should I check before using DC Cable Voltage Drop Calculator?

Check DC source voltage, Current, One way cable length and Conductor cross section. Use the exact units shown beside the controls and replace any example values with your own inputs.

Source page last modified (UTC): 2026-10-01T18:56:36+00:00

This profile describes the tool. It does not execute it or supply a professional certification.