Amps to Watts Calculator
Convert electrical current in amps to power in watts.
Results update as you type.
How it works
Converting electrical current to power tells you how much energy per second a device uses, and this calculator finds it from the current and voltage. You enter the current in amps and the voltage in volts, and it returns the power in watts. The relationship is the fundamental power equation: power equals current times voltage. Power measures the rate at which electrical energy is consumed or delivered, so a device drawing more current or running at a higher voltage uses more power. For example, a device drawing 10 amps at 120 volts consumes 1,200 watts. This conversion is useful for figuring out the wattage of an appliance from its current rating, estimating running costs, sizing generators and power supplies, and checking that a circuit's total load stays within safe limits. Knowing the power lets you calculate energy use over time in watt-hours or kilowatt-hours, which is what electricity bills are based on. As with the reverse conversion, this simple formula applies exactly to direct current and purely resistive alternating-current loads; circuits with motors or other reactive components have a power factor, so their real power is the product of current, voltage, and that factor. Enter the current and voltage to compute the power in watts.
P = I × V
Power in watts equals the current in amps multiplied by the voltage in volts. This is the basic electrical power equation: power is the rate of energy use, and it grows with both the current flowing and the voltage driving it. It applies directly to direct current and resistive loads.
Source:Electrical engineering
We review all our tools from time to time to ensure accuracy.
Worked example
How to use this calculator
- 1
Enter your values
Enter current and voltage.
- 2
Adjust the options
Fine-tune any options to match your situation.
- 3
Read your result
Power updates instantly as you type — no button to press.
Frequently asked questions
How do you convert amps to watts?
Multiply the current in amps by the voltage in volts. A device drawing 10 amps at 120 volts uses 1,200 watts. The calculator does this instantly. This applies exactly to direct current and resistive loads; for AC circuits with motors, a power factor also enters the calculation.
What is the power equation?
The electrical power equation states that power equals current times voltage. It links the three key electrical quantities: knowing the current and voltage gives the power, the rate of energy use. Rearranging it also lets you find current from power and voltage, or voltage from power and current.
Why would I convert amps to watts?
You convert amps to watts to find a device's power consumption from its current rating, which helps estimate electricity costs, size generators and power supplies, and ensure a circuit's total wattage stays within safe limits. Power in watts is also the basis for energy use in watt-hours, which utilities bill for.
How does this relate to my electricity bill?
Your electricity bill charges for energy in kilowatt-hours, which is power in kilowatts multiplied by hours of use. Converting a device's current draw to watts, then to kilowatts and multiplying by hours, tells you its energy consumption and cost. So this conversion is the first step in estimating what a device costs to run.
Does this work for alternating current?
It works exactly for direct current and purely resistive AC loads such as heaters and incandescent lamps. For AC circuits containing motors, transformers, or other reactive loads, the real power also depends on the power factor, so the true wattage is current times voltage times the power factor, which is less than one for such loads.