How to check a PC's power consumption

Updated: 03/05/2023 by Computer Hope
Various power meters.

Computers today come in many shapes and sizes. Consequently, the power they use (measured in watts) differs based on their components, model, and form factor. The following sections provide a few methods for users to determine how much power their desktop or laptop computer regularly uses.

To proceed, select a method from the list below or read through them all to see which best suits your needs.

Using a hardware monitor utility

This method for checking power consumption involves downloading and installing a free tool that shows you the real-time power draw of each component in your computer.

  1. Open your preferred Internet browser and navigate to the Open Hardware Monitor download page.
  2. Click the Download Now button.
  3. Click the downloaded file and follow the installation instructions.

Starting the installation process for Open Hardware Monitor.

  1. After installing and launching Open Hardware Monitor, you can expand each component's section to see how many watts it is currently using.

GPU power usage in watts via Open Hardware Monitor.

Using an online tool

There is a handy online tool offered by OuterVision that approximates your system's total power draw, provided you know the make and model of its internal components.

  1. Open your preferred Internet browser and navigate to the OuterVision Power Supply Calculator.
  2. Scroll down a bit and click the Basic tab (A).
  3. Fill out each of the component fields (B).
  4. Click the Calculate button (C).

Power consumption calculator from OuterVision.

  1. In the Results section, Load Wattage displays the estimated power consumption of your computer.

Power results from OuterVision tool.

Using a wattmeter

Suraielec plug-in wattmeter.

While a wattmeter does have an associated upfront cost, once purchased, it's a simple and accurate way to see your system's total power draw.

After buying a wattmeter (we suggest Amazon, Newegg, or your local computer store), plug it into the wall, and then plug your desktop or laptop power cord into it. The built-in screen displays how much power your computer uses in real-time.


You can use a wattmeter with other household electronic devices, such as a coffee maker or television.