Electrical Calculators

Free calculators for electrical work. Size wire, calculate voltage drop, determine breaker ratings, and plan service panels — all NEC compliant.

Calculate voltage, current, resistance, and power from any two known values.

Calculate voltage drop across a wire run based on distance, current, and wire gauge.

Determine the correct wire size based on amperage, distance, and voltage.

Determine the correct breaker size for a circuit based on load and NEC rules.

Calculate total electrical demand to size your home's service panel.