calculators
Voltage Drop Calculator
Estimate voltage drop and percentage in wire runs. Enter voltage, current, one-way length, cable area, material, and circuit type.
Frequently Asked Questions
What is a typical planning target?
Many projects use 3% as a planning target for branch circuits, but local rules and project requirements vary.
Copper or aluminum wire?
Copper has lower resistivity (about 0.0175 ohm mm2/m vs 0.0282 for aluminum), so aluminum usually needs a larger cross-section for the same drop.
Is this an electrical code calculation?
No. This is a basic voltage drop estimate for planning only. Always follow your local electrical code and consult a licensed electrician for real installations.