Electrical Power Calculator – Voltage × Current (Watts)
Calculate electrical power in watts from voltage in volts and current in amperes, with a simple P = V×I example and practical limitations.
Electrical power tells you the rate of electrical energy transfer. The calculator multiplies entered voltage in volts by current in amperes and returns watts. This simple direct product is especially useful for basic DC examples and resistive cases.
How it works
P = V × I, with voltage in volts (V), current in amperes (A), and electrical power in watts (W).
Example
A device operating at 12 V and drawing 2 A has an estimated power of 12 × 2 = 24 W under this simple model.
How to use
- Enter the voltage in volts, including the relevant sign if using signed values.
- Enter the current in amperes, not milliamperes; convert 500 mA to 0.5 A first.
- Calculate the product in watts and check whether the simple DC/resistive model matches your circuit.
Key features
- Voltage and current input
- Transparent multiplication formula
- Watt output in SI units
Common uses
- Check basic electronics homework
- Estimate DC device power
- Compare simple load examples
Limitations to know
For AC circuits with phase difference, real average power can require power factor rather than simply multiplying RMS voltage and current. Do not treat this result as an electrical safety certification.
Frequently asked questions
How many watts is 12 V at 2 A?
The simple product is 24 W.
Can I use milliamperes directly?
No. Convert milliamperes to amperes by dividing by 1,000 first.
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