How to Use the Free Calculator
Choose your voltage, wire material, and wire size. Enter the amps your equipment uses and the distance from the power source to the equipment in feet. Use the distance one way—don’t double it. Leave “Parallel sets” at 1 unless you’re using parallel wiring.
The calculator updates automatically to show how much voltage is lost along the wire. Try different wire sizes to compare the results. The suggested size is based on voltage drop; an electrician can confirm the right wire for your installation.
What Is Voltage Drop?
Voltage drop is the amount of voltage lost as electricity travels through a wire. Longer distances, higher current, and smaller wires can increase that loss. This calculator helps you compare wire sizes and see the estimated voltage reaching your equipment.
Single-Phase and Three-Phase Voltage Drop Calculator
Choose single-phase or three-phase to match your circuit. You can select a preset voltage or enter a custom voltage, then compare copper or aluminum conductors using your load and wire length.
Understanding Your Results
Voltage drop percentage: The percentage of your starting voltage lost along the wire.
Volts dropped: The estimated number of volts lost between the source and equipment.
Voltage at load: The estimated voltage reaching your equipment.
Maximum run at 3%: The longest one-way distance for your selected wire and load at a 3% voltage drop.
The wire suggestion considers voltage drop. Final wire selection also depends on the load, breaker, and installation requirements.
Share This Free Calculator
Have a website, electrical guide, or training resource? You’re welcome to link to this free voltage drop calculator so your readers can compare wire sizes and check voltage loss. No account is needed to use it.
Need Help With an Electrical Project in Temecula?
Contact BP Electrical Temecula for help planning your wiring, checking an existing circuit, or installing electrical equipment.