About WireGauge

WireGauge is a free wire size reference: a complete AWG chart, a wire size calculator and an AWG to mm² converter. It is written for homeowners and DIYers planning a circuit, and checked carefully enough for electricians to use as a quick reference.

There are no accounts and nothing to install. Your inputs stay in the page address, so you can bookmark a result or send it to someone.

Where the numbers come from

Wire sizes come from the ASTM B258 gauge formula, resistance from the published resistivity of copper and aluminum, and current ratings from the National Electrical Code (NEC). The methodology page lists every formula, table and source.

What WireGauge is not

WireGauge is a general reference, not an electrical contractor or engineer, and it doesn't give advice for your specific installation. It applies the NEC's general rules and doesn't replace your local code, a permit or an inspection. When in doubt, ask a licensed electrician or your local inspector.