Electrical Calculators
Last updated: October 2026
Electrical Power Calculator
Calculates electrical power in watts from voltage and current using P = V Γ I.
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.
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.
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 Γ R rearranged for you.
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.
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.
Inductive Reactance Calculator
Calculates inductive reactance (XL) for a coil or inductor in an AC circuit at a given frequency.
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.
Voltage Drop Calculator
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.