What Are Watts? A Simple Explanation

A watt (W) is the basic unit of electrical power. Power describes how fast energy is being used or delivered at any moment. The higher the wattage, the more energy something consumes in a given second.

In electrical systems, watts are tied to two other measurements: volts (V) and amps (A). Volts are the electrical “pressure,” and amps are the amount of electrical current flowing. When you multiply the two together, you get watts:

Watts = Volts × Amps

This formula helps explain why watts matter. A device running at 12 volts and using 2 amps is consuming 24 watts of power. The same wattage applies to everyday items you already know—like light bulbs, which often carry labels such as 40W, 60W, or 100W. These numbers don’t just describe brightness; they represent how much electrical power the bulb uses when it’s on.

Watts are also used to rate chargers, appliances, and batteries. A high-wattage charger, for example, can provide more power and charge a device faster. A high-wattage appliance, like a microwave or heater, uses more electricity and therefore increases energy costs.

It’s important to remember that watts measure instant power, not how much energy is used over time. For that, we use watt-hours (Wh)—the total number of watts consumed each hour. So while watts tell you how powerful something is in the moment, watt-hours tell you how long a device can run on a certain amount of stored energy.

In short, watts make it easy to understand how much electrical power a device uses or delivers. Whether you’re choosing light bulbs, comparing chargers, or evaluating batteries, wattage gives you a clear measure of performance and energy use.