Wire size depends on three main factors: current load (amps), circuit distance, and voltage drop requirements. Always size wire to handle 125% of the continuous load. Calculate proper wire gauge, voltage drop, and ampacity for safe electrical installations. This site offers many simple-to-use calculators and wire ampacity charts to aide you in properly sizing wire and conduit in compliance with the NEC. This comprehensive wire size calculator guide provides the formulas, tables, and step-by-step calculations needed to determine the correct wire size for any electrical application, from residential. Calculate the minimum wire gauge (AWG) for your electrical circuit based on amperage, voltage, distance, and conductor material.