About this tool
Estimate voltage drop along copper or aluminium cable from length, current and cross-section.
ΔV = k·L·I·ρ ÷ A, with k = 2 for single-phase DC/AC, √3 for three-phase, resistivity ρ = 0.0172 (copper) or 0.0282 (aluminium) Ω·mm²/m at 20 °C, and L the one-way length.
Formula: ΔV = kLIρ/A
Example: Conductor = Copper, System = Single-phase / DC, Cable length, one way (m) = 30, Current (A) = 16, Cross-section (mm²) = 2.5, Supply voltage (V) = 230 → Voltage drop (V) = 6.605, Voltage drop (%) = 2.87%.
Ignores reactance and temperature rise. Electrical work must follow your local wiring regulations and a qualified electrician.
Quick steps
- Enter your values — every field shows its unit.
- Press Calculate (or Try an example to see how it works).
- Read the results and copy them if you need them elsewhere.
The calculation runs in your browser. Nothing you type is sent to 1CLIK.
FAQ
How does the Voltage Drop Calculator work?
ΔV = k·L·I·ρ ÷ A, with k = 2 for single-phase DC/AC, √3 for three-phase, resistivity ρ = 0.0172 (copper) or 0.0282 (aluminium) Ω·mm²/m at 20 °C, and L the one-way length.
What should I keep in mind?
Ignores reactance and temperature rise. Electrical work must follow your local wiring regulations and a qualified electrician.
Is my data sent anywhere?
No. The numbers stay on your device; the page only shows the result.