You have likely been using a laptop computer for many years and regularly recharging it. Sometimes, you may even leave it plugged-in for multiple days at a time, primarily if you use a laptop docking station while you work. You might be thinking should you leave it plugged in? Do you know if it is adding unnecessarily to your energy bill?

How many watts does a laptop use? An average laptop uses around 25-55 watts. However, this will vary depending on your particular laptop. To determine the exact amount of watts used by your laptop, you can check the product specifications. 

To power your laptop correctly, you should always charge it with the factory included wall charger. The factory wall charger provides the exact amount of watts needed for your laptop to charge.

Your laptop’s wattage can usually be found on its underside and in its specification document from the manufacturer. If you do not use the proper charger, the laptop may charge improperly/slowly, or worse – get damaged. 

How Many Watts are Used by Laptops? 

There are hundreds of brands of laptops around and thousands of different models. Some will use the same amount of watts, but they typically fall within the range of 25-55 watts. The number of watts used by a laptop varies for many reasons, including: 

  • Screen size – The larger your laptop screen is, the more watts it will consume. Additionally, as the brightness setting on your screen increases, your wattage does too. 
  • CPU – If you have a laptop with a high-end CPU like an Intel Core i9 processor, you will be using more watts than a basic Core i3 processor. 
  • Graphics card – A GPU with more graphics processing power also uses more watts. If you are using graphics-intensive programs or playing video games, you will use even more watts. 
  • The wattage of the power adapter – If the power adapter has a higher wattage, your laptop will use more watts to charge. The most common laptop chargers are rated either 60W or 90W. You can determine what yours is by looking at the charging brick. 
  • Hard drive type – If your laptop has a traditional hard drive as opposed to a solid-state drive, it will use more watts to spin the disk. 
  • Ambient temperature – The hotter your laptop is, the more watts it will use. Always make sure you have proper clearance for cooling, and perhaps look into a cooling pad or mat. 

Watts Used by Popular Laptops

As stated before, all laptops use a different amount of watts unless they are the same exact model (and running at the same performance levels). Here is a look at the watts of some of the most common laptops. 

Laptop:  MacBook Air MacBook Pro 16”  Microsoft Surface Laptop 3 15” Dell XPS 15 HP Spectre X360 14
Watts 8-25  12-45 10-35 watts 20-40 watts 39 watts
Power Adapter rating 30 watts 96 watts 65 watts 100 watts 65 watts
Screen Size 13 inches 16 inches 15 inches 15.6 inches 13.5 inches
CPU M1 Processor M1 Processor AMD Ryzen 5 or 7 Intel Core i5, i7, or i9 Intel Core i5 or i7
Hard Drive 

Type

Solid State Solid State Solid State Solid State Solid State

As you can see, each laptop comes with a different power adapter rating size and uses a different amount of watts. Depending on what you are doing with your laptop, the watts used will differ. For example, if your laptop is in sleep mode and plugged in, it will use a minimal amount of watts, likely less than 1 W. 

On the other hand, if you are playing video games on maximum screen brightness, you will be at the higher end of the watt usage. 

With USB-C charger capabilities becoming more common, it is possible to charge various laptops with the same charging connector. However, you will have to use a power supply rated at or above the minimum power input for your particular laptop model. 

How Many Kilowatts Hours Does a Laptop Use?

If you are interested in how many watts laptops use, you may also be wondering how many kilowatt-hours of energy they use. A kilowatt-hour (kWh) is the measure of the energy consumed by a device.

Kilowatt-hours are used for energy billing by electric utility companies in the US. If you know how many kilowatt-hours your laptop uses, you can estimate your laptop’s energy costs!

To calculate the kilowatt-hour per month for your specific laptop, you would need to multiply its power rating by the number of hours you use it per month, then divide by 1,000. Take the 16” Macbook Pro, for example, it has a 65 Watt power adapter, and we will assume a daily usage of 9 hours, 5 days a week. 

In this example, the kilowatt-hours per month will be 9  x 5 x 65 ÷1,000, which equals 2.925 kWhs!

The Price to Charge Your Laptop

In the US, the average kilowatt-hour price is around 13.3 cents per kWh. The above example will cost about $0.38 per month to run a 16” Macbook Pro. As you can see, a laptop’s electricity costs are pretty insignificant in the grand scheme of things. 

How to Check Your Laptops Wattage

Since you are interested in knowing how many watts a laptop uses, you probably want to know your particular laptop’s wattage. These days, it is easy to check the wattage of your laptop. You can use any of the following methods: 

  • Check the label on your power adapter. It should say a number with a “W” after it. For example, 45 W. Note- some laptops work with more than one wattage of power supply.
  • Check the underside of your laptop for wattage or voltage and amperage. If you find something like “19.5V – 2.31A”, you can use these numbers to calculate watts by merely multiplying them together. In this case, the answer is 45W.
  • Look online and find the manufacturer’s specs. Find the full model number of your computer and Google it. You should be able to find the power and watts specifications easily.
  • Read the product manual or box that your laptop came in. There is a high chance that the wattage is listed there too.
  • If you exhaust these options, you can contact the laptop manufacturer through email or phone and inquire about your laptop’s wattage. 

Will Your Laptop Use More Watts Plugged in All Day? 

Leaving your laptop plugged in all day could very likely use more watts than if you unplugged it.

Leaving it plugged in is very nuanced since all laptops are different. Some newer laptop models automatically stop drawing power when fully charged and in sleep or standby mode. In this case, they would not use more watts if they are plugged in all day. 

However, many laptops do not have this feature and will use a tiny amount of watts while they are plugged in all day. Some testing has soon this number to be as low as 0.1-0.2 watts. 

Ways You Can Get Your Laptop to Use Less Watts

If you want to use fewer watts on your laptop because you are concerned about the extra pennies you will have to pay, there are easy methods you can use to reduce your watt usage. Here are the best ways to use fewer watts on your laptop: 

  • Turn the screen brightness and volume down. 
  • Only run one program at a time. 
  • Avoid resource-heavy programs, like video games and graphic design software. 
  • Ensure your laptop has adequate cooling. Use a cooling dock or laptop stand to allow for good airflow. 
  • Turn your laptop off or put it to sleep immediately when you are finished using it. 
  • Do not leave your laptop plugged in when you are not using it. As noted earlier, it may use extra watts. 
  • Only use it when you absolutely need to. 

Conclusion 

There are many flavors of laptops, possibly thousands of different models. Because there are so many, it is difficult to assign one number to the number of watts a laptop uses. On average, laptops tend to use 25-55 watts. 

The wattage varies based on the laptop’s screen size, the laptop’s settings(brightness and volume), and what you are doing on the laptop. To find the watts of your laptop, you can look at your power adapter, the bottom of your laptop, search your laptop model on the internet, or consult the laptop manufacturer.