What is the Voltage Drop Calculator?
Long or thin cables lose voltage, causing dim lights, hot wires and poorly running motors. Enter the cable size (mm²), one-way length, current and supply details to get the voltage drop in volts and percent, the voltage at the load and the power wasted as heat.
How to use the Voltage Drop Calculator
- Enter supply voltage, phase and current.
- Enter cable size, length and material.
- Check the drop is within 3–5%.
Formula
Drop = 2 × L × I × ρ ÷ A (single-phase / DC) or √3 × L × I × ρ ÷ A (three-phase), with ρ = 0.0172 Ω·mm²/m for copper.
This Voltage Drop Calculator is 100% free, needs no signup and runs privately in your browser – on phone, tablet or computer.
Last updated: · By NodifyTech