What Is the Volts to Watts Calculator?
This tool converts an electrical voltage and current into power, expressed in watts. It uses the fundamental power equation \(P = V \times I\), where \(P\) is power (watts), \(V\) is voltage (volts), and \(I\) is current (amperes). It works for any DC circuit and for AC circuits where the power factor is 1 (purely resistive loads).
How to Use It
Enter the voltage in volts and the current in amperes, then read the resulting power in watts. For example, a device running at 12 V drawing 2 A consumes 24 watts. This is handy for sizing power supplies, batteries, fuses, and chargers.
The Formula Explained
Electrical power is the rate at which energy is delivered. The product of voltage (the "push") and current (the "flow") gives power:
$$P = V \times I$$One watt equals one volt-ampere in a DC or unity-power-factor circuit. To get kilowatts, divide watts by 1000.
Worked Example
Suppose a USB charger outputs 5 V at 3 A. Power:
$$P = 5 \times 3 = 15 \text{ watts}$$A 230 V appliance pulling 10 A draws:
$$230 \times 10 = 2{,}300 \text{ watts } (2.3 \text{ kW})$$
FAQ
Does this work for AC? It is exact for DC and for resistive AC loads. For reactive AC loads, multiply by the power factor: \(P = V \times I \times PF\).
How do I convert watts to kilowatts? Divide the watt value by 1,000.
Can I go backwards from watts to amps? Yes — rearrange to \(I = P \div V\).
