How many watts to charge a laptop?

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The need to charge your laptop every night is very common. We all know that using your laptop when it’s low on the battery can become frustrating. However, the issue with laptops is that it’s difficult to know exactly how many watts to charge a laptop uses when you’re not looking at the power adapter. Let’s look at some simple ways to calculate how many watts are being used by your laptop, so you can see whether or not it needs a charge before bed.

How to find out how many Watts your laptop uses when charging?

The first step is to look at your laptop charger and find the output voltage. It will be a standard number such as 19 volts or 20 volts, but you want to make sure it’s not abnormal for your specific model of laptop. Also, note that laptops use either 120V (US) or 240v (international). Once you know what voltage you’re working with, now you need to know the ampere. A laptop usually has a 3.25 ampere.

So Now,

20 V 3.25 A = 60 Watt 

It means your laptops use 60-watt power approximately every hour.

Is there a minimum wattage required to charge a laptop?

Yes, there is a minimum wattage required to charge a laptop. However, it varies from laptop to laptop. For example, some laptops require as low as 29 W to charge, and some as high as 31 W. You can also use a power bank or a power adapter to charge your laptop.

Moreover, there is also a maximum wattage. For example, if you are using an AC adapter with more watts than your computer’s power supply can handle, the system will not use all that power and may cause damage. Therefore, you should always check out what type of input voltage range your laptop requires before buying any chargers or adapters for it. If you wish to purchase other chargers or adapters, make sure they have at least as many volts as the original charger/adapter because otherwise, these could damage your machine too! It can happen very quickly, so; please take care when doing this.

Factors Affecting Power Consumption of Laptops

Here we will discuss several factors that affect the power consumption of the laptop.


The first factor here is the battery. The type of battery the laptop uses will impact how many watts are used to charge this device and how long it can be charged before needing another recharge cycle.

Laptop age:

The age of the laptop is also an essential factor in power consumption when charging a laptop with traditional lithium-ion or nickel-cadmium (NiCd) batteries. For example, suppose you’ve noticed that your laptop doesn’t seem to last as long on a single charge anymore. In that case, this isn’t due to wear and tear from using your computer over time. Instead, it’s because these types of batteries have been reported by some researchers not staying at full capacity after only around 500 charges/discharges. To address this issue, you need to use new technology such as a lithium-ion polymer (LiPo) or nickel-metal hydride (NiMH), which means that you’ll need to look for laptops with these types of batteries if your laptop is more than five years old.

Laptop adapter:

Another important consideration is the wattage of its power supply. A high-wattage adapter will provide a much faster charge to your battery, so it’s important not to choose one with less than 65 watts as this would impact how quickly you can use your computer for tasks such as gaming or watching videos.

Dual graphics card:

Another factor that affects the power consumption of laptops is a presence of a dual graphics card. It has been shown that laptops with this feature will use more power than those without it, but the difference is relatively small and won’t make any significant change to your battery life if you have one or not.

Central processing unit:

Another factor that contributes to the power consumption of a charge is the central processing unit. The higher number of cores a CPU has, the more work it can do at once and thus uses up power. It is another reason why having an i-Core would be better than, say, a dual-core, even though you have lower clock speeds.

This list shows that when looking for laptops with longer battery life, you should consider these factors: low wattage, graphics card (if needed), central processing unit cores. If your laptop doesn’t need to handle high-end games or videos, choose one without a graphics card, as this will save energy and make the price difference smaller between models with and without them.

Frequently Asked Questions

Q. How do I choose the right charger for my laptop?

You can choose the right charger for your laptop by measuring the voltage and ampere of your current model. A good replacement charger should have an output equal to or higher than watts required by the laptop, be in the same voltage range as the original adapter, all cords are included with the package, etc. Check product descriptions carefully before buying a new one!

Q. Which one is better: USB or AC charger for laptops?

Neither, the best one is a detachable AC/DC adapter. This way, you get more power, and your battery lasts longer! USB chargers or AC ones are good options for laptops that work on low voltages if it’s not available.

Q. How many watts does my laptop use?

Laptops can vary in voltage and wattage depending on model and usage, but to give you an idea, a 15-watt LED screen usually uses 45W while a 70% brightness LCD screen requires 60 W approximately every hour. You can check this information with product descriptions or manuals of the device before buying extra chargers, so you don’t overpay for them later!


If you’re looking to charge your laptop, follow these tips for the best outcome. When charging a laptop battery, the voltage must match what was designed by the manufacturer of your device. It will ensure that both laptops and batteries last as long as they possibly can. We hope our advice today gives you helpful information about how many watts should be used when charging a laptop.

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