Voltage Drop Calculator
Calculate voltage drop in electrical circuits based on wire length, current, and conductor properties
About this calculator
This voltage drop calculator helps electricians, engineers, and DIY enthusiasts determine the voltage loss in electrical circuits based on wire length, current flow, and conductor properties. Voltage drop occurs when electrical current travels through conductors, causing a reduction in voltage at the load end. This tool ensures your circuits operate efficiently and meet electrical code requirements by calculating whether voltage drop stays within acceptable limits, typically 3-5% for most applications.
How to use
Enter the wire length (one-way distance), current draw in amperes, conductor material (copper or aluminum), wire gauge size, and system voltage. The calculator will instantly display the voltage drop amount, percentage drop, and whether it meets standard electrical code requirements for your specific application.
Frequently asked questions
What is acceptable voltage drop percentage?
Generally, voltage drop should not exceed 3% for branch circuits and 5% total for the entire electrical system according to NEC guidelines.
Why does wire gauge affect voltage drop?
Larger wire gauges have lower resistance, reducing voltage drop. Smaller gauges create more resistance, increasing voltage loss over distance.
How does conductor material impact calculations?
Copper has lower resistance than aluminum, resulting in less voltage drop. Aluminum requires larger wire sizes to achieve equivalent performance.