Electrical Calculators

Circular Mil Area Calculator

Calculate wire cross-sectional area in circular mils, square inches, and square millimeters from diameter in mils or AWG gauge number.

Electrical Conduit Fill Calculator (40% Rule)

Calculate conduit fill percentage for any wire combination. Verify NEC 40% maximum fill for EMT, PVC, and rigid conduit with multiple wire sizes.

Generator Transfer Switch Sizing Calculator

Size a generator transfer switch by total load amps and circuit count. Get amp rating, manual vs automatic options, and code requirements for home backup power.

Cable Cross-Section Sizing Calculator

Find the minimum cable cross-section in mm² for a given current and cable length. Uses IEC ampacity tables and voltage drop limits (metric system).

Power Factor Correction Calculator

Calculate the capacitor bank size needed to correct a lagging power factor to a target value. Find required kVAR and capacitance in microfarads.

Prospective Short Circuit Current Calculator

Calculate the prospective short circuit current (Isc) at a point in a single-phase or three-phase electrical system using transformer and cable impedance.

Wire Gauge Size Calculator (AWG)

Find the correct AWG wire size for a given current load and circuit length. Checks both NEC ampacity and voltage drop limits.

LC Resonant Frequency Calculator

Calculate LC circuit resonant frequency, inductance, or capacitance. Find angular frequency, Q factor, and wavelength for radio, filter, and oscillator design.

LED Resistor Calculator

Calculate the correct resistor for LED circuits. Find series resistor ohms, wattage, and power dissipation for single LEDs and LED strings.

Lumens to Watts / Lux to Footcandles Converter

Convert lumens to watts, watts to lumens, lux to footcandles, and calculate illuminance from area. Compare LED, CFL, halogen, and incandescent bulb efficiency.

Radiation Dose Unit Converter

Convert radiation dose units between Gray, rad, Sievert, rem, millisievert, Becquerel, and Curie. Includes weighting factors and real-world dose reference.

RC Circuit Time Constant Calculator

Calculate the RC time constant (τ = RC) for resistor-capacitor circuits. Find capacitor charge and discharge voltages, 63% charge time, and 5-tau settling time.

Three-Phase Power Calculator

Calculate three-phase AC power: real (kW), apparent (kVA), reactive (kVAR), line current, and power factor. Covers balanced star and delta configurations.

Transformer Sizing Calculator

Calculate transformer kVA rating, turns ratio, primary and secondary currents, and efficiency. Size a transformer for single-phase and three-phase loads.

kVA to kW Converter (and kW to kVA)

Convert between apparent power (kVA) and real power (kW) using power factor. Calculate kVA, kW, kVAR, and power factor for AC electrical systems and UPS sizing.

Motor Full Load Amps (FLA) Calculator

Calculate full load amperage (FLA) for AC motors. Find NEC-required breaker size, wire gauge, and overload protection for single-phase and three-phase motors.

Peak / RMS Voltage Converter

Convert between peak, RMS, and peak-to-peak voltage for AC signals. Calculate power, crest factor, and waveform parameters for sine and square waves.

Voltage Drop Calculator

Calculate voltage drop in electrical wire runs based on wire gauge, length, current, and material. Ensure compliance with NEC 3% and 5% guidelines.