Electrical Calculators
Fast, accurate engineering calculators built with zero server latency. Select a calculator below or search directly.
Electrical Fundamentals
Ohm's law, power, voltage, current, resistance, and energy calculations
Ohm's Law Calculator
Calculate voltage, current, resistance, and electrical power with interactive Ohm's Law formulas.
Electrical Power Calculator
Calculate real power (W/kW), apparent power (VA/kVA), and reactive power (VAR) for DC, single-phase, and 3-phase AC systems.
Electric Current Calculator
Calculate electric current (Amperes) from power and voltage or voltage and resistance.
Voltage Calculator
Calculate electrical voltage (potential difference) from current and resistance or power and current.
Resistance Calculator
Calculate resistance in Ohms (Ω) from voltage and current, voltage and power, or power and current.
Electricity Cost & Energy Calculator
Calculate appliance power consumption and estimated electricity bills daily, monthly, and yearly.
Kilowatt-Hour (kWh) Calculator
Convert electrical power and operating hours into kilowatt-hours (kWh) and megawatt-hours (MWh).
Kilowatts to Horsepower (kW to HP) Calculator
Convert between Kilowatts (kW) and Horsepower (HP) using mechanical and metric horsepower standards.
Wire & Cable
Voltage drop over distance and conductor gauge sizing
Voltage Drop Calculator
Calculate voltage drop, percentage loss, and remaining load voltage for DC, single-phase, and 3-phase circuits over distance.
Wire Size Calculator (AWG & mm²)
Calculate recommended minimum conductor gauge and cross-sectional area to keep voltage drop within allowable limits.
EV Charger Circuit Sizer
Size a Level 2 EV charger circuit: breaker from the 125% continuous-load rule, copper wire from the correct temperature column, and a voltage-drop check that can upsize the wire.
Conduit Fill Calculator (NEC Chapter 9)
Calculate conduit fill percentage and minimum raceway size for EMT, PVC, RMC, and FMC under NEC 40% fill rule.
Battery & Solar
Battery runtime, required capacity, inverter sizing, and solar PV sizing
Battery Runtime Calculator
Estimate battery runtime in hours and minutes from voltage, capacity (Ah), load power (W), depth of discharge, and inverter efficiency.
Battery Capacity Calculator (Ah / Wh)
Calculate the required battery capacity in Amp-hours (Ah) and Watt-hours (Wh) for a specified load and runtime.
Inverter Size Calculator
Calculate recommended continuous and peak surge inverter wattage for home backup, RV, and off-grid solar setups.
Solar Panel Sizing Calculator
Calculate required solar panel array wattage and panel count based on daily energy consumption and peak sun hours.
Power Systems & Protection
Circuit breaker sizing, fuse selection, and power factor analysis
Power Factor Calculator
Calculate power factor, real power (kW), apparent power (kVA), and reactive power (kVAR) in AC systems.
Fuse Sizing Calculator
Calculate recommended fuse current ratings for continuous and non-continuous electrical circuits.
Circuit Breaker Sizing Calculator
Calculate standard circuit breaker ampere ratings applying the continuous load 80% / 125% rule.
Motor Full-Load Current & Circuit Sizer (NEC Article 430)
Size motor branch circuit conductors (125% FLC), inverse-time breakers (250% Max), fuses, and overload protection (NEC 430.32).
Electronics & Components
Series/parallel resistors, resistor color codes, and capacitor reactance
Resistor Series & Parallel Calculator
Calculate total equivalent resistance for any number of resistors connected in series or parallel.
Resistor Color Code Calculator & Visualizer
Decode 4-band, 5-band, and 6-band resistor color bands with interactive visual preview and tolerance range.
Capacitor & Reactance Calculator
Calculate capacitive reactance (Xc), stored energy (Joules), and series/parallel capacitor network values.