Voltage Drop Calculator
Calculate voltage drop in electrical circuits based on wire length, gauge, current, and material
About this calculator
The Voltage Drop Calculator helps electricians, engineers, and DIY enthusiasts determine voltage loss in electrical circuits based on wire specifications and current load. Voltage drop occurs when electrical current flows through conductors, causing power loss and reduced efficiency. This tool ensures your electrical installations meet code requirements and operate safely by calculating whether voltage drop exceeds acceptable limits (typically 3% for branch circuits and 5% total). Proper voltage drop calculations prevent equipment malfunction, overheating, and electrical hazards.
How to use
Enter the wire length (distance from source to load), select the wire gauge (AWG size), input the current draw in amperes, and choose the conductor material (copper or aluminum). The calculator will instantly compute the voltage drop percentage and actual voltage loss, helping you determine if your wire selection meets electrical code standards.
Frequently asked questions
What is acceptable voltage drop for electrical circuits?
Most electrical codes allow maximum 3% voltage drop for branch circuits and 5% total system voltage drop to ensure proper equipment operation.
How does wire gauge affect voltage drop?
Larger wire gauges (lower AWG numbers) have less resistance, resulting in lower voltage drop over the same distance and current load.
Why does conductor material matter for voltage drop?
Copper has lower electrical resistance than aluminum, producing less voltage drop. Aluminum requires larger wire sizes to achieve equivalent performance to copper.