Electrical Calculators

Last updated: October 2026

Electrical Power Calculator

Calculates electrical power in watts from voltage and current using P = V × I.

Three Phase Power Calculator

Calculate the real output power (kW) of a three-phase electrical system from line voltage, line current, power factor, and efficiency.

Panel Schedule Load Calculator (by Circuit Type)

Estimate the current on a panel from its lighting, receptacle, appliance and motor circuits, applying NEC-style demand factors, and compare it with the main breaker rating.

Motor Full Load Current Calculator

Calculate the full-load current drawn by a single-phase or three-phase AC motor from its horsepower, voltage, efficiency and power factor.

Ohm's Law Solver (V = IR)

Solve Ohm's law for voltage, current or resistance: pick the unknown, enter the other two values and get V = I × R rearranged for you.

Wire Ampacity Calculator

Find the safe current-carrying capacity of a copper or aluminum wire based on AWG size, ambient temperature, and number of bundled conductors.

Short Circuit Current Calculator

Compute the available short-circuit current (ASCC) at a fault point downstream of a transformer, accounting for transformer impedance and cable impedance to the fault location.

Motor Starting Current Calculator

Calculate the full-load running current of a three-phase AC motor from its horsepower, voltage, and efficiency ratings.

Inductive Reactance Calculator

Calculates inductive reactance (XL) for a coil or inductor in an AC circuit at a given frequency.

Watts to Amps to Volts Calculator (DC and AC)

Solve for current, power or voltage in a DC, single-phase AC or three-phase AC circuit from the other two, with the power factor applied and power entered in watts, kilowatts or horsepower.

Wire Size Calculator

Find the smallest standard copper wire size (14 AWG to 750 kcmil) that meets both NEC ampacity and your voltage-drop limit for a DC or single-phase AC circuit.

Calculate voltage drop on a copper or aluminum wire run from load current, one-way length, wire size (14 AWG to 500 kcmil) and single- or three-phase supply, with the percentage against the NEC 3% guideline.