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Voltage Drop Calculator
Calculate voltage drop in electrical circuits. Find correct wire gauge for any distance and current to minimize power loss.
Enter any 2 of the 4 values — the rest will be calculated automatically.
Volts
Amps
Ohms Ω
Watts
Voltage
12 V
Current
2 A
Resistance
6 Ω
Power
24 W
Ohm's Law: V = I × R | P = V × I | P = I² × R | P = V² / R
How to Use the Voltage Drop Calculator
Enter your values above for an instant result. This tool uses verified formulas and is optimised for users in USA, Canada, UK, Australia. All calculations happen in your browser — your data is never sent to our servers.
Frequently Asked Questions
What is acceptable voltage drop?
NEC recommends maximum 3% voltage drop for branch circuits and 5% for the full circuit including feeders.