How Many Watts Does a Laptop Charger Use? 2021 Guide

Mobile devices such as laptops use less electricity when plugged into the wall rather than an external display. As a rule, it is believed that a laptop battery completely charges per day, although it can take less than 20W to recharge in some cases. 

For this reason, 70% of the energy remains in the charger, and 30% is released as heat into the atmosphere

This Hewlett-Packard 15 model represents the typical home computer. This unit takes 41W for a battery refill. Like any other piece of information, or data, of course, this value varies. 

Each power supply unit does not dissipate the same amount of power. Though the fluctuations are very tiny, it is not much of a problem.

The capacity of a battery is a reliable reflection of how well it works. You have to buy a new battery if your laptop battery fails.

How Many Watts Does a Laptop Charger Use?

According to the United States Department of Energy’s most recent laptop power consumption estimate, a standard laptop charger uses 50 watts of electricity, equal to 5-kilowatt hours

Using an average, a WH implies that if a laptops is used for eight hours a day, it would cost 5p a day to keep it running.

Charging is Tied to Power Consumption

A giant notebook or even when not in use consumes more power than a tablet PC for computationally demanding tasks. A bigger battery will take more time to charge than a smaller one.

The Larger Laptop: ThinkPad W510

I attached my power adapter to the ThinkPad W510, a regular computer that takes up slightly less desk space. In idleness, or with no task to do, the laptop uses 28 watts of power

It is already in medium wattage (browser, image processing, office programs, e-mail). And at the highest level? My batteries are giving me a reading of 88 watts of charge

However, the actual speed of the processor tends to vary greatly when doing processor-intensive tasks like video conversion, mainly when it is doing so rapidly. Thus, it is calculated that if I use the average, it is roughly 39 watts!

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This system only uses 1.9 watts of power in standby mode. This machine is now in a highly relaxed state, with a one-and-twenty-a-watt output. What if the laptop is removed from the socket? The AC supply uses just 0.8 watts in the standby mode. 

The total energy consumption is more prominent when the laptop is not plugged in, but it is a minimal number when the battery is merely powering.

The Smaller Laptop: ThinkPad x100e Power Consumption

The wattage was calculated with a highly efficient machine in mind. A smaller model of the ThinkPad X100e is available as well. A slow processor and lower-powered graphics card are part of the bundle. 

Is it better for the environment? This thing has been on constantly all day, and it’s still in standby mode when it’s not in use.

Without a linked device, it will only use 90 watts of electricity. In idle mode, the less energy-intensive laptops consumes 15 watts. In between medium and high, the system reaches 24 watts

This notebook has an output of 35 watts when the CPU is at 100 percent utilization (i.e. when a video is playing). This machine uses less power so that I can leave it on all day without conservation concern.

How Many Watts Does a Laptop Use When Charging?

How Many Watts Does a Laptop Charger Use

You should be able to find the amount of power your laptop requires to run using the general estimate of “around 90 Watts per hour.”

In essence, you have to make sure the laptops power cord has not been cut. There will be several resources to help you collect that kind of material.

For viewing the laptop on the right, my 17-inch gaming laptop (which needs a little more energy for surfing the web) takes 180 watts per hour.

To find out the battery charging voltage and capacity values for your laptop, look at the charger that came with it.

Factors that affect battery life

The bottom line is that your laptop uses much less power than most chargers will typically output while working, which is why knowing the amount of Watts your charger puts out doesn’t help you fully predict how long it will take to charge.

It consumes less energy when on battery, but when charging, even less than what is mentioned on the charger. These printers’ chargers are limited to printing the maximum number of pages: (which is usually around 90 Watts).

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Power consumption varies by laptops but will depend on how you use it. When your laptop is not in use, it consumes minimal energy. For example, internet use would require more energy.

Same thing: The phone works the same way: the more things you do on it, the battery life shortens.

Additional factors that affect your laptop battery lifetime:

Screen size to see a larger picture, you’ll need a higher-powered monitor. Laptops use less capacity and therefore have longer battery life spans

1) Internal components

Graphics Cards (especially those with a dedicated GPUs) use more power. You will see the number of hard drives you have, the more power it takes to run.

Power is drawn from the CPU as well; however, depending on what you’re doing on your laptop. The CPU can affect how much energy you use. When CPU-intensive tasks are finished, your laptop can use more fuel.

2) External peripherals

Anything that isn’t plugged into your laptop can use more power: a cursor, keyboard, gaming controller, or display. A significant number of choices are possible.

Additionally, peripherals that are not in service should be unplugged!

3) Laptop Adapter

There is only one way to assess How Many Watts Does a Laptop Charger Use. Every inch laptop has its power cord, and the screen’s display port determines power requirements.

The plug on a 15-inch laptop charger uses a 65-watt power supply, while a 17-inch laptop charger uses a 90-watt power supply.

With these two adapters today, your laptop can charge based on wattage.

Therefore, it is fair to assume that your laptop would use between 60 and 90 WH of power.

4) Central Processing Unit

The CPU is an essential component of any device or laptop’s functioning machine or system. In this case, “CPU” stands for the CPU. The OS depends on the CPU to do the work.

With so many different software packages available to improve the performance of any CPU regardless of the version of Windows, it does not matter which version you use. Our understanding will increase, but the battery life will decrease when we do. CPU use has the power to do consume up to the battery runs out.

The converter supplies the energy in the form of watts and works the laptop. As a result, the extra load on the CPU will require more power.

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Also, be aware that there’s additional weight on the laptop. On the contrary, that is why it is known as an adapter. Since it permits us to take advantage of watts in some cases, it’s highly advantageous.

5) Dual graphics card

if you’re one of the few who use heavy apps, then you know the secrets of the smartphone’s battery drain.

A graphics card with heavy software loaded onto it to allow resolutions and clarity-enhancing features; Often, they assist in running and using applications that they are designed for.

The existence of a graphics card changes the maximum wattage that a battery can supply and, thus, increases the amount of energy that can be consumed when charging.

Batteries and adapters still battle in such circumstances, so you get the adapter battery overheating and why you get a laptop going bad.

FAQs ― How Many Watts Does a Laptops Charger Use?

  1. How much power does a laptop charger use?

    ( 4.42 watts )
    That's wasted energy. It's just an example of another vampire. According to the Berkeley Lab, cell phone chargers use 0.26 watts, and laptop power bricks use approximately 4.42 watts of energy.

  2. Can I use a 90 watt charger on a 65 watt laptop?

    You can use a 90 watt AC adapter or a battery adapter. The statement is correct; it will help your battery to charge. But, the question is: are you aware that you can't use a 19V adapter on a laptop that is 18.5V only?

  3. Can I charge my laptop with a lower wattage charger?

    Absolutely Yes. Regardless of the wattage, you can use a less powerful charger for your laptop to avoid throttling its output. For instance, charging a laptop with 45 watts of power could compromise the performance.

  4. Can a 65W charger for 45W laptop?

    Yes, you read that correctly. The amount of power a charger can deliver is measured in watts. A 45w computer won't run at full capacity without an equally large, 65w power supply, and vice versa.


Using the information on the laptop’s underside will give you an estimate of How Many Watts Does a Laptop Charger Use. A significant feature is shown as “Output” because it is mentioned under “Input.” To calculate power consumption, you multiply the voltage by amperage.

It is necessary to provide the power consumption at full power, but slightly higher power consumption is anticipated. Because of this, when the notebook is charging. The system will use up to seventy percent of the network bandwidth. It is also impossible to precisely calculate the value with a voltmeter.

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