Calculate the voltage drop across an electrical wire run to ensure your wiring meets code requirements. Enter the wire gauge, circuit amps, distance, and system voltage to see if the voltage drop stays within the NEC-recommended 3% for branch circuits or 5% total for feeders and branch circuits combined.
Enter Your Measurements
Results
Voltage Drop
5.27
volts
Voltage Drop
4.39
%
Voltage at Load
114.7
volts
Power Loss in Wire
84.3
watts
Meets 3% Code (1=Yes, 0=No)
0
Formula
How to Use This Calculator
How to Use
- 1
Enter the wire gauge in AWG (14, 12, 10, 8, 6, 4, 3, 2, or 1).
- 2
Enter the load current in amps.
- 3
Enter the one-way distance from panel to load.
- 4
Enter the system voltage.
Frequently Asked Questions
Frequently Asked Questions
What is acceptable voltage drop?
How do I reduce voltage drop?
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About This Calculator
This calculator uses the formula: Voltage Drop = (2 × 10.75 × Amps × Distance) ÷ Circular Mils | Drop % = (Voltage Drop ÷ System Voltage) × 100. All calculations follow industry-standard methods. Results are estimates — always verify with a licensed professional for structural or code-compliant work.
Built and maintained by the CalcSmart team. Last updated March 2026.
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