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How Do Laptop Charger Watts Work? (Read Here!)

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Watts is an internal unit used to measure electrical power. It indicates the amount of energy or joules processed/ consumed every second. Most devices come with a Watt rating, meaning their power usage per hour, and really powerful devices need over 1000 Watts (1 Kw to operate.) 

What does this have to do with your charger?

It means a good Laptop charger provides the adequate amount of Wattage your Computer needs to run. Typically, most manufacturers attach the appropriate adapter for their products and provide the Wattage information in the Computer’s manual if the user replaces it later.

How much Wattage does my Computer need?

Most Laptops need between 45-70 Watts to run. However, more powerful computers need more Wattage. For example, gaming Computers and workstations can use up to 100 Watts or more to power their various components and simultaneously charge their batteries.

Components like graphics cards, processors, Wi-Fi cards, and high-powered displays contribute to the higher wattage requirement. As we mentioned, you can determine your Laptop charger details by checking your computer manual or finding some answers online.

If you’re up for some basic maths, you can calculate the exact Wattage of your Computer using the information you find at the bottom of your charger.

If you find something like this— OUTPUT: 19VDC 3.42A, you can multiply the values to get the total Wattage for your battery. In this case, it rounds down to 65W. For charger shopping, you want to note the Output voltage (19VDC), and the Amperage if you can. They’ll both help in your search for a charger. 

Understanding Voltage and Current

Laptop Charger Watts (How it Works!) - Understanding Voltagesand Current in PC
Voltage is like water pressure, and Ampere is like the flow rate. Together they determine the power requirement of your PC.

Understanding how Watts works might help to have some foundational knowledge on Voltage and Ampere.

Voltage is the pressure of an electric circuit, and Ampere is the measure of the rate of flow of an electron. To better understand the relationship between them, think of electricity as water flowing through a pipe. Voltage is the water pressure, and Ampere is the flow rate, and together they determine the power requirement of your PC.

If the Voltage or Ampere is out of place, that can affect your PC performance and, in extreme cases, even damage some components. 

To calculate Wattage, you multiply Volage by Ampere. 

How to find the Right Charger for your Computer? 

Armed with information about your computer wattage needs and charger requirements, you can shop for a charger replacement more confidently.

However, all chargers are not created equal, and you have three real options when you’re searching for a capable replacement.

OEM Laptop Chargers (Original Equipment Manufacturer) 

OEM accessories are the best replacements for your computer accessories. Often, they are a 1:1 recreation of the charger/ mice/ keyboard that shipped with your PC on purchase. However, they are not the most affordable choice. Because OEM accessories are manufactured by third-party brands and not in-house, they usually go at a premium, but you’re guaranteed quality.

They are also easy to find and purchase too. Getting a new charger can be as simple as logging onto the manufacturer’s site and requesting a new charger. However, tracking down the chargers can be a pain for older devices. The manufacturers might have discontinued the product line, and you’ll likely find counterfeits on sites like eBay and Amazon.

Universal Charger

Most computer chargers are the same on the inside. So as long as you have the same connector and Wattage rating, there’s no reason why you can swap chargers, even if they come from different brands/ manufacturers.

Universal chargers were built with this information as a base. They sell generic chargers with common connector types that work for different brands on the market. They are all produced by third-party brands and are considerably cheaper than OEM Laptop Chargers. 

However, they are not without their shortcomings. You’ll need to get the pin connectors just right to avoid picking up the wrong charger, they typically don’t come with warranties or any guarantor of quality, and they may not be a tight fit for your device. 

Third-party Laptop Chargers

Laptop Charger Watts (How it Works!) - Third-party Laptop Chargers

Some brands/manufacturers dedicate themselves to producing high-quality laptop chargers and accessory replacements on par with the quality of OEM products. Just like shopping on a manufacturer’s website, you can search for particular laptop models and find working replacements. 

However, the problems with OEM persist with third-party manufacturers. Most do not have an extensive catalog of products and will likely stock only the most popular replacements from the biggest brands. You might have to settle for a Universal charger made from a somewhat respectable brand. 

Can I use a charger with a Higher Wattage on my Laptop?

Technically, you can, but you have to make sure the Voltage and Polarity match up even if the Ampere doesn’t. Referring back to our analogy of the rive, as long as the pressure is the same, your PC won’t draw power that it cannot use.  

As a rule of thumb, choosing devices with a close enough Wattage requirement as possible is better.

Can I use a charger with a Wattage Charger on your Computer?

You definitely can, but we advise against it. Using a lower wattage charger means your PC only gets a fraction of the power it needs to run properly.

Since your PC is not constantly blasting the processor or graphics card, a lower Wattage charger might not be a problem while you’re idling. However, the moment you launch an application, your laptop battery might begin to discharge or charge improperly.

Over time, you might blow a fuse in your Laptop’s power supply or seriously damage your PC’s charger or other important components.


Understanding your PC charger’s Wattage and how it’s related to the concepts of voltage and Ampere can arm you with the information you need to make smarter buying decisions in the future. As a result, you can save yourself a lot of time and money while you’re shopping for chargers, replacing batteries, and estimating your battery health.

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Pigtou Editorial Team

A group of tech enthusiasts who find pleasure in troubleshooting and resolving various issues. When we're not engaged in writing, we typically enjoy playing table football or spending time with our office dog.
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