Voltage Drop Calculations

This is a voltage drop calculator for finding the minimum wire size based on allowable voltage drop in a Branch Circuit.

This is only to help eliminate voltage drop! it in no way reflects conductor sizing based on other factors. For example a short run of copper wire with a 20 amp load will come up with #14 wire while the code asterick notes require minimum of #12. Consult the National Electrical Code for more details.

Please enter your values

120 Volts Copper... Single Phase
208 Volts Aluminum Three Phase
240 Volts
277 Volts
480 Volts
Distance in feet, one-way
Total amperage of circuit


This is your minimum wire size.