How to Fix: Black Border on Laptop Display when Connecting HDMI to TV

Infopackets Reader 'Jackie' writes:

" Dear Dennis,

I just read the article you wrote about 'How to Fix: Windows 10 Black Border (Shrinking Screen)' and have a similar question. I just upgraded to Windows 10; I have an HP laptop and have connected it to my big flat screen TV. The problem is that as soon as I plug in my HDMI cable to connect the HDTV to the laptop, the laptop displays black borders on the sides of the screen. How can I fix that? "

My response:

The reason you have black borders on the side of the screen whenever you connect your HDTV through the HDMI cable is because the laptop and the television are using two different aspect ratios. For example, your laptop may produce 1600x1200 standard resolution (4:3 aspect ratio), but the HDTV does 1920x1080 (16:9 aspect ratio). If the aspect ratios do not match, then one of the displays will have a black border around the edges, depending on which display you set as primary.

How to Fix: Black Border on Laptop Display when Connecting HDMI to TV

To fix mismatching aspect ratios (and resolutions) when connecting two displays together, you will need to do one of two things:

1. Ensure the aspect ratios match. If your laptop can change to a resolution that supports the same aspect ratio as your HDTV, that should fix the problem with the black borders. It's been a while since I've hooked up an external monitor to my laptop. Based on my experience, however: if the aspect ratios do match and the display resolutions are not the same, then the device with the lower resolution will only display part of the full screen at a time. In this case, there will be no black border on the edges of either screen, but you will need to 'scroll' through the screen with the smaller resolution in order to see the 'full screen', so to speak. For example, if your laptop could do 1600x900 display resolution and you're trying to hook it up to an HDTV with 1920x1080 resolution, both display ratios would match at 16:9, but the laptop won't show the entire full screen (1920x1080), providing the HDTV is set as your primary display. For the record you can calculate aspect ratios online.
    
2. The easiest way to get around all of this is to simply output to the external device (HDTV) instead of outputting to both the laptop and the HDTV at the same time. If you set the laptop's power options to not go to sleep when you close the lid, then you can close the lid as soon as you connect to the HDTV and then use only the HDTV as your viewing source. Unless both devices support the exact same resolution (1920x1080 for example), this is the best way to approach this problem. When you're finished using the HDTV, you can open the laptop display then unplug the HDTV cable and your laptop's display should come back on. You can also adjust which devices gets the primary display (either on the HDTV or laptop) through your graphic card settings.

I hope that helps.

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About the author: Dennis Faas is the owner and operator of Infopackets.com. With over 30 years of computing experience, Dennis' areas of expertise are a broad range and include PC hardware, Microsoft Windows, Linux, network administration, and virtualization. Dennis holds a Bachelors degree in Computer Science (1999) and has authored 6 books on the topics of MS Windows and PC Security. If you like the advice you received on this page, please up-vote / Like this page and share it with friends. For technical support inquiries, Dennis can be reached via Live chat online this site using the Zopim Chat service (currently located at the bottom left of the screen); optionally, you can contact Dennis through the website contact form.