Power Calculator
Calculate electrical power, voltage, current, resistance, energy, or operating time using common electrical formulas. Enter your known values and get an instant result.
Calculate Power
Calculation Result
What Is a Power Calculator?
A Power Calculator is an electrical calculation tool used to determine power, voltage, current, resistance, energy, or time when other electrical values are known. Electrical power describes the rate at which electrical energy is transferred or consumed by a device.
Power is normally measured in watts (W). Depending on the available information, electrical power can be calculated using voltage and current, current and resistance, or voltage and resistance.
This calculator provides several commonly used electrical formulas in one tool, making it useful for students, electricians, technicians, engineers, DIY projects, and anyone working with basic electrical calculations.
Power Calculator Formulas
The correct formula depends on which electrical values you already know.
Power equals voltage multiplied by current.
Power equals current squared multiplied by resistance.
Power equals voltage squared divided by resistance.
Energy equals power multiplied by operating time.
Electrical Power Symbols and Units
The formulas used by the calculator use standard electrical symbols:
Measured in watts (W).
Measured in volts (V).
Measured in amperes or amps (A).
Measured in ohms (Ω).
How to Use the Power Calculator
Select a Calculation
Choose whether you want to calculate power, voltage, current, resistance, energy, or time.
Enter the Known Values
Enter the two electrical values requested by the calculator.
Click Calculate
Press the Calculate button and the applicable electrical formula will be applied automatically.
Review the Result
Your calculated value and the formula used will appear in the result panel.
Power Calculation Example
Suppose an electrical device operates at 120 volts and draws 5 amps of current.
Using the standard power formula:
Therefore, the electrical device consumes 600 watts of power under those conditions.
Why Use an Electrical Power Calculator?
Electrical calculations are used when selecting equipment, estimating electrical loads, checking appliance consumption, studying circuit behavior, and comparing electrical devices.
Instead of manually rearranging electrical equations, this Power Calculator automatically selects the correct formula based on the values you provide. This reduces calculation time and helps avoid basic arithmetic errors.
Common Uses
The calculator can be useful for appliance calculations, electronics projects, electrical circuits, battery systems, lighting systems, educational exercises, power supplies, motors, and general electrical planning.
Frequently Asked Questions
Electrical power is the rate at which electrical energy is transferred or consumed. It is commonly measured in watts.
The most common electrical power formula is P = V × I, where P represents power, V represents voltage, and I represents current.
Multiply the voltage in volts by the current in amps. For example, 12 volts multiplied by 5 amps equals 60 watts.
Yes. If current and resistance are known, use P = I² × R. If voltage and resistance are known, use P = V² ÷ R.
A watt is a basic unit of power. One kilowatt is equal to 1,000 watts.
Yes. Select the energy option and enter power in watts and time in hours. The calculator will return energy in watt-hours.
Yes. You can use the calculator to perform basic electrical power calculations directly in your browser.