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How to measure your PC’s power use, and why it matters

A person using 1Password on a desktop all-in-one computer while sat at a desk. There are two laptops next to them on the desk.
1Password / AgileBits

If you are building your own PC, you might be interested in how much power your PC uses. Whether you're playing games, or it is sitting idle, it's a good idea to know when the PC costs the most to run.

You could use this information to decide when is the best time to use your PC if you are looking for ways to cut down on energy costs.

Fortunately, there are several different tools you can use to monitor this important statistic. Some are built right into your operating system, while others will require a separate download. You can also purchase certain external devices to keep tabs on your desktop’s energy output.

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Difficulty

Easy

Duration

10 minutes

What You Need

  • Desktop PC or laptop

  • Power monitor plug (optional)

To make it easier to figure out which method is best for you, we’ve rounded up all our preferred power draw monitoring tools, with instructions for each category.

CoolerMaster PSU calculator
Christian Cawley / Digital Trends

Use an online calculator

If you want to just get a rough idea of how much power your system uses, then a quick calculator can save you a lot of hassle with taking measurements.

Step 1: Head to the CoolerMaster Power Supply Calculator page. This tool is designed to give you information about what the best power supply unit (PSU) your computer needs, but the information is provides is useful beyond this.

Step 2: This is a straightforward tool, requiring you to simply select the right CPU, motherboard, GPU, etc.

Step 3: Input as much information as you can, including components, coolers, whether you've overclocked your system, and any other relevant information you can think of.

Step 4: As you enter the information, the recommended PSU wattage is displayed on the right.

A readout of component statistics with the HWInfo tool.
Jon Martindale / Digital Trends

Add it up with HWInfo

HWInfo is an excellent tool for tracking all sorts of aspects of your PC, including its power usage. But you'll have to do a little math.

Step 1: Head to the HWInfo official site and download the app. Install it like you would any other, following the on-screen instructions.

Step 2: Run the app, and when prompted, select Sensors only >OK.

Step 3: HWInfo has a lot of detail, so it can be a bit overwhelming to start with. The information you need is here -- you just have to find it.

Scroll down until you find the CPU section, then look for CPU Package Power. That's the total power your CPU is pulling at that time. Next, look for your graphics card, and find either Total Graphics Power, or Total Board Power.

Add these figures together to get a good idea of how much power your system uses. If your motherboard and memory support it, you may have power sensors for those too. Add that together for greater accuracy.

Note: Also consider putting your PC in a load state and then retaking the readings so you know how much power you use while gaming or other tasks.

The various component fields on the Be Quiet PSU Calculator.
Be Quiet!

Give Be Quiet a try

Another web-based monitoring tool you can use is the Be Quiet PSU Calculator. Opting for a more a la carte approach to your PC’s individual components, Be Quiet allows you to input stats for everything from your CPU and GPU to graphics cards and cooling systems.

After inputting all the values, click the Calculate button at the bottom of the page to figure out what your PC’s peak power consumption is.

Person using Windows 11 laptop on their lap by the window.
Microsoft

Use Windows’ monitoring tools

While not as robust and advanced as the downloadable power draw tools we’ve mentioned, Windows 11 has a few tricks up its sleeve when it comes to energy monitoring. One of these tools is called Resource Monitoring — one of the latest additions to the Windows Widgets dashboard.

Resource Monitoring allows you to track things like your PC’s processor utilization, memory usage, and GPU temperature. The one caveat is that Resource Monitoring is only available through Microsoft’s Dev Home Preview app. However, you can use the Windows energy saver settings on desktop and laptop computers on Windows 11.

Image of Kill-A-Watt Meter
Daniel Martin/Screenshot / Kill A Watt

Measure power consumption with hardware

If you want to get the best readings for the overall power usage of your computer, you will need to measure the connection from a wall outlet with an external power meter, such as a .

This power meter will let you take an accurate measurement of your PC’s power consumption, and is available from Amazon, Home Depot, hardware stores, and other retailers for around $20 to $40.

Simply plug it in, plug your PC's power cable into it, then turn your PC on. The power use will be displayed on the Kill A Watt meter.

PC power usage FAQ

What consumes the most power in a PC?

Generally speaking, both a computer’s CPU and graphics card are going to be the two biggest culprits when it comes to power consumption.

Can I leave my PC on 24/7?

The simple answer is yes. The more complex answer is also yes, but you may want to invest in a few accessories.

For the most part, desktop computers are designed to constantly run, but you’ll want to make sure the PC is placed in an area where it can properly dissipate heat. Any out-in-the-option location is better than a closed cabinet door.

If your computer is housed in a less than ideal place, or you want to exercise some extra caution, you can always purchase a or CPU cooler.

Choose your PC upgrades with power in mind

Now that you know how to check your system's power usage, you might want to think carefully about future upgrades. The best graphics cards might make your games pretty, but they do use a lot of power.

Michael Bizzaco
Former AV Contributor
Michael Bizzaco has been selling, installing, and talking about TVs, soundbars, streaming devices, and all things smart home…
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