In this article, we are going through “How Many Watts Does a Laptop Use?”

Laptops are used extensively in today’s society. They take up a major share of the global electricity market and emit about 4% of the world’s carbon emissions. The question we all want to know is, How Many Watts Does a Laptop Use?

The answer might not be as simple as you think. A laptop’s power usage varies by model and configuration, and it also depends on whether or not it’s plugged into an outlet or running off its battery. Check out this comprehensive guide to find out what your laptop uses, when it uses that power, and what you can do to lower your energy spending!

How Many Watts Does a Laptop Use?

Our first question is how much power is being used by a given laptop?

Nerd Power

Dell Inspiron 13 7000

Our second question is where does that power come from?

At home: Your power company.

Your power company. In the workplace: The wall plug.

The wall plug. On the road: USB battery chargers and mobile charging stations.

Basic laptops: 25 to 40W

Notebook makers often tout basic laptops as the lightest, most portable option. However, the battery life of basic laptops is also very poor.

Basic laptops have to keep a large amount of power in reserve when they’re not being used. To get through a workday or basic daily use, a laptop’s power supply must produce a continuous flow of power – usually around 25 to 40 watts.

Laptop power usage when plugged in

laptop power usage when plugged in
laptop power usage when plugged in

As you might expect, a laptop uses more power when it’s plugged in than when it’s off. However, some models will draw significantly more power than others when they’re plugged in. For example, the Kobo Glo HD has a peak power draw of 151W when off, but only 105W while plugged in. That’s more than 12 times more power draw than the top-of-the-line laptop (although the Kobo’s power consumption when on is still quite high).

The table below is a look at the average power consumption of several popular laptops. The average is just that: an average, which means it’s just a sampling of the many models. It doesn’t take into account power use that’s non-negligible or cumulative, such as a laptop that’s sitting idle for hours.

Laptop power usage when charging

To measure the power of your laptop and what it uses, plug it into a wall outlet and let it run for a while. The more it charges, the higher the wattage and power consumption of the battery.

Most laptops only use a fraction of the power they’re supposed to, in comparison to the amount of time they’re not plugged in. This is called power consumption.

A common benchmark is to see how much power it would take to completely discharge a battery and restore the laptop to 100%.

How much power does it take to completely discharge a battery?

Like most things, the answer depends on how full your battery is. As soon as you open the laptop, you consume much more power than the initial battery discharge.

While at the same time, the battery increases in the capacity as it discharges.

Laptop power usage while running on battery

All of the main manufacturers make laptop computers that can be turned on without plugging them into an electrical outlet. This isn’t always the case with netbooks and ultraportables, however. In this case, your laptop is just “docked” in its docking station and will need an outlet to be powered on.

The components of a laptop can also shut off while in sleep mode, which can further reduce your laptop’s power consumption. Check out our comprehensive guide to learn about all of the different types of power-saving modes available on laptop computers.

Laptop power consumption while plugged in

Laptops that have a battery can be plugged into an electrical outlet in either “low” or “high” power modes. In “low” mode, the battery drains more slowly and allows the laptop to operate for longer.

The difference between wattage, energy used and cost

Let’s take a closer look at how a laptop’s power usage breaks down, and you’ll quickly notice that “wattage” is actually misleading. While the measurement has a physical value and a definition (the amount of power that a device is capable of delivering), what people really care about is the number of watts used. For example, my laptop uses about 24 watts when it’s plugged into an outlet and running off its battery.

But what if you take a $500 laptop and plug it into a wall outlet. For the purpose of this article, let’s call it a MacBook Pro. This year’s model uses 2.9 watts, compared to 2.5 watts last year.

However, on a daily basis, that MacBook Pro is not likely to be generating 2.9 watts of power.

What to do if you want to lower your budget?

If you’re not willing to sacrifice any power or performance, here are a few ways you can lower your energy consumption:

Use a notebook that runs on batteries or an AC adapter instead of using a wall outlet.

Use a notebook that can be turned on and off and uses significantly less power when in use. For instance, a Windows 8.1 device with an Intel Atom processor can go about 10 hours between charges. A Macbook Air, on the other hand, lasts a maximum of 2.5 hours.

Take advantage of low-power modes or power-saving features in your notebook. For example, Windows 8.1 has a Power Saver option that can lower your usage by 30%.

In a laptop or netbook configuration, be aware of what kind of battery it has.


If you’re considering buying a laptop, choose one with efficient design and features, such as big power saving options and portable power banks. Consider buying an additional charger, especially if you have a long-term commitment. It’s definitely worth it to invest in the proper gear to conserve energy and reduce your environmental impact!