Wire & Cable Calculators: Free Tools for Sizing & Voltage Drop

Determine the correct wire gauge and cable size for any electrical installation with our free online wire and cable calculators. Whether you are wiring a residential outlet, sizing conductors for a commercial panel, or planning long cable runs, these tools calculate ampacity, voltage drop, and derating factors instantly. Enter your load current, circuit length, and insulation temperature rating to receive NEC-compliant wire size recommendations for both copper and aluminum conductors. Avoid costly mistakes from undersized wiring that creates fire hazards or oversized cables that waste budget. Each calculator includes voltage drop percentage, conduit fill requirements, and AWG-to-mm² conversions. Electricians, contractors, and DIY homeowners rely on these precise tools to ensure safe, code-compliant installations every time. No signup required—calculate wire size directly from your phone or desktop.