Power & Energy Calculators: Free Electrical Tools for Watts & kWh
Calculate electrical power and energy consumption with our free online power and energy calculators. Whether you need to find wattage for an appliance, estimate monthly kWh usage, or convert between power units, these tools deliver instant, accurate results. Simply input voltage, current, or runtime values to discover real energy costs and efficiency metrics. Ideal for homeowners comparing appliance ratings, electricians sizing panels, and engineers optimizing system loads. Each calculator includes built-in unit conversions and clear formula breakdowns, eliminating manual math errors. From single-device wattage to full-building energy audits, our power and energy calculators streamline electrical planning. No downloads required—access everything from your browser, mobile or desktop, and start calculating smarter energy use today.
-
Capacitor Energy Calculator
Calculate the energy stored in a capacitor using capacitance and voltage. Instant results for electronics, RC circuits, and energy storage applications.
-
Electrical Power Calculator
Calculate electrical power for DC and AC circuits quickly. Find real, apparent, and reactive power using voltage, current, and power factor values.
-
Negative Sequence Voltage Calculator
Calculate negative sequence voltage easily using this 3-phase voltage unbalance calculator. Ideal for motor protection and system fault analysis.
-
Voltage Unbalance Calculator
Calculate voltage unbalance using the ANSI method and sequence components (VUF). Input phase magnitudes or phasors (Va, Vb, Vc) to get % unbalance, VUF, and step-by-step results.
-
Mechanical Power Calculator
Instantly compute mechanical power by entering force and speed (or torque and angular velocity). Engineers’ quick tool for accurate power output estimation.
-
Effective Radiated Power Calculator
Easily calculate the Effective Radiated Power (ERP) of an antenna system using transmitter power, cable loss, and antenna gain in watts or dBm.
-
Sponsored
-
Speed to Power Calculator
Instantly convert rotational speed (RPM) and torque to mechanical power in watts, kilowatts, or horsepower using this Speed to Power Calculator.
-
Torque to Power Calculator
Easily calculate power output from torque and rotational speed (RPM). Find mechanical power in watts or horsepower using this torque-to-power calculator.
-
Pump Power Calculator
Calculate hydraulic and motor power for pumps using flow rate, head, efficiency, and fluid density. Ideal for engineers and system designers in water and industrial applications.
-
Wheel Horsepower Calculator
Calculate wheel horsepower (WHP) and brake horsepower (BHP) instantly. Estimate drivetrain losses and engine efficiency for accurate vehicle performance analysis.
-
Pump Shaft Power Calculator
Calculate the required pump shaft power using flow rate, head, efficiency, and fluid density. Ideal for hydraulic engineers and pump selection applications.
-
Extruder Power Calculator
Estimate the motor power required for plastic or rubber extrusion based on output rate, material type, and efficiency with this accurate Extruder Power Calculator.
-
Sponsored
-
Flywheel Power Calculator
Calculate flywheel power, torque, and stored energy from mass, speed, and radius. Ideal for mechanical design, motor systems, and energy recovery analysis.
-
Air Conditioner Electricity Cost Calculator
Estimate your AC running cost per hour, day, or month. Calculate electricity usage, power rating, and energy cost to manage home cooling expenses efficiently.
-
Battery Bank Size Calculator
Calculate battery bank size for your solar, inverter, or backup system. Get total capacity in Ah and kWh by entering load, runtime, and system voltage.
-
Active Power Calculator
Calculate real power in AC circuits using voltage, current, and power factor. Perfect for electrical engineers, students, and energy system analysis.
-
Steam Engine Power Calculator
Calculate steam engine power using pressure, piston area, stroke, and RPM. Perfect for mechanical engineering, engine design, and performance analysis.
-
Vertical Jump Power Calculator
Calculate the power generated during a vertical jump using body weight, jump height, and time. Ideal for athletes, coaches, and fitness enthusiasts.
-
Sponsored
-
Received Power Calculator
Calculate received power in RF or wireless systems using transmitted power, gains, losses, and distance. Ideal for engineers and communication system analysis.
-
Peak Envelope Power Calculator
Calculate PEP for RF transmitters using RMS voltage or current. Ideal for amateur radio, RF engineers, and transmitter design.
-
Average Power Calculator
Calculate average power in AC or DC circuits using voltage, current, and power factor. Ideal for engineers, students, and energy efficiency analysis.
-
Three Phase Power Calculator
Calculate active, reactive, and apparent power in three-phase AC systems using voltage, current, and power factor. Ideal for engineers, electricians, and students.
-
Reactive Power Calculator
Calculate reactive power in AC circuits using voltage, current, and power factor. Ideal for engineers, electricians, and students analyzing inductive/capacitive loads.
-
kVAR to Farad Calculator
Convert kVAR to capacitance in Farads instantly. This calculator helps size power factor correction capacitors for single-phase or three-phase electrical systems.
-
Sponsored
-
Micro-Farad to kVAR Calculator
Convert microfarads (µF) to reactive power (kVAR) easily. Ideal for calculating capacitor bank ratings and power factor correction requirements in AC systems.
-
Voltage to Energy Calculator
Quickly convert voltage, current, and time into electrical energy in joules or watt-hours using this Voltage to Energy Calculator for circuits and power systems.