Instantly determine the correct American Wire Gauge for your circuit. Enter your current, voltage, distance, and material to get a precise recommendation with full safety analysis.
Circuit Parameters
Calculation Results
Standard copper wire specifications per NEC guidelines
| AWG | Diameter (mm) | Area (mm²) | Max Current (Cu) | Max Current (Al) | Resistance (Ω/1000ft) | Usage |
|---|
Picking the wrong wire gauge is one of the most critical mistakes possible in any electrical wiring project. If you are working on a circuit, installing a long cable run, or dealing with an industrial power system, you will have to learn how to properly choose a wire gauge according to American Wire Gauge (AWG) standards. For detailed information on wire gauges, please check out our article “American Wire Gauge: AWG Wire Size Guide.” Use the AWG Wire Size Calculator for free online!
The Wire Size Calculator is a completely free and online calculator designed to help electricians, engineers, hobbyists, and students to determine the right size of wire needed for their electrical circuits. In order not to calculate wire sizes manually using some mathematical equations, it is sufficient just to enter the required data and receive instant responses from this program.
Tip: According to the NEC, the maximum allowable voltage drop for branch circuits is 3%, while total drop for feeders and branch circuits is 5%.
Tip: The NEC recommends a maximum voltage drop of 3% for branch circuits and 5% total (feeder + branch). The calculator flags these thresholds automatically.
Now press the Calculate Wire Size button. This calculator uses the circular mili formula [CM = ρ x K x I x L / VD] and confirms the obtained result using National Electrical Code (NEC) ampacity charts to find the minimum wire size.
The output consists of seven values which are everything you need to know regarding the operation of your circuit:
Furthermore, there is a color-coded status bar showing the result – “Optimal” (≤3%), “Acceptable” (≤5%) or “High Drop”.
It is applicable for multiple audiences, from professional electricians designing a circuit prior to installation, to engineers calculating the sizes of feeders and branch circuits for their construction project. Moreover, it may be used for home applications such as garage subpanel and EV charging circuit installations. This tool will be especially helpful if your circuit length exceeds 50 feet.
The AWG Wire Size Calculator makes it impossible to make mistakes in determining the required size of the wire. It uses the circular mils voltage drop method and National Electric Code ampacity values to calculate the result instantly. Read our guide to learn more about the American Wire Gauge System and properties of wires at CalcVersa.
“For official wiring standards, refer to the NEC 2023 — National Electrical Code. For workplace electrical safety requirements, see OSHA Electrical Safety Standards.”
