About Electrical Calc Pro

Electrical Calc Pro provides free electrical calculators for homeowners, DIYers, and licensed electricians. Our tools follow NEC (National Electrical Code) guidelines and are designed to give you fast, accurate results for wire sizing, voltage drop, load calculations, and more.

We built these tools because electrical calculations are not difficult — they are just tedious. A quick wire gauge check or voltage drop calculation should take 30 seconds, not require a lookup table or engineering software.

Important Disclaimer

Always consult a licensed electrician before performing electrical work. Our tools are for reference and planning purposes. Local codes may differ from NEC requirements, and electrical mistakes can be dangerous or fatal. These calculators help you understand and plan — they do not replace professional judgment or inspection.

How We Build Our Tools

Each calculator is based on published NEC formulas and industry-standard tables. Wire resistance values use published copper and aluminum conductor tables. Voltage drop calculations use the standard formula. Breaker sizing follows the 80% continuous load rule. We update tools when NEC code cycles change.

Contact

Questions or errors to report? Contact us here. We respond within 1-2 business days.