Technology Explained

How to Check the Power Output of a USB Port

Dan Price 13-04-2018

Given so many devices now power themselves using a USB connection, it’s important to know how much power the USB port on your laptop can supply. If a device tries to draw more power than the port can supply, you risk killing the port 5 Ways to Fix a Malfunctioning USB Device or Port on Linux Can't get your USB devices to work properly in Linux? Try these troubleshooting tips to get things working again. Read More —or even starting an electrical fire


Not all USB ports are created equal. Your machine might have a mix of USB 2.0 and USB 3.0 connections Why You Should Upgrade To USB 3.0 It’s been quite a while since USB 3.0 has been included in motherboards, but now we've come to the point where most devices and computers come with the new and improved ports. We all know... Read More , each of which might have different outputs. Knowing a USB plug’s power output also helps to determine if there are any problems with your ports. For example, if a port is not charging gadgets as quickly as normal, you might discover its power supply is not as high as it should be.

Thankfully, it’s easy to measure a USB port’s power output.

How to Check the Power Output of a USB Port

How to Check the Power Output of a USB Port power usb 670x387

To check the power output of a USB port on Windows, download the free USBDeview. It’s a portable app, so no installation necessary.

Once you fire up the app for the first time, you will see a complete list of all the USB devices that you have ever used, as well as a list of your USB ports. The ports which are currently active on your machine are highlighted using a green checkbox.


To see the details of a USB port, double-click on its name. You will see all the information about the port, including when it was last used, whether it is safe to unplug any currently-connected device, and a whole lot more.

You need to locate the Power field. It will show you how many milliamperes the port can supply.

If you would like to learn about electrical safety, we covered the topic in more detail when we looked at the safety of Kodi boxes How to Check Your Kodi Box for Electrical Safety Cheaply made Kodi boxes can be a fire hazard. In this article, we explain why this is the case and help you find out if your Kodi box is affected. Read More .

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  1. Steve Wilson
    September 16, 2019 at 11:49 pm

    It would be nice to be told exactly where this menu was located. The fact that it exists is nice. No other info is more than a little frustrating.

  2. nope
    August 25, 2018 at 7:34 pm

    This is not true. The "power" tells you that how many amp are drawing from the port by the accessary.

    • Tony Coleby
      November 11, 2018 at 12:46 pm

      It shows a range of active devices for me between 8-800ma so seems to be how much they are drawing, yes.