Can the Macbook Air (2015 model) power a second external monitor via it's USB port (using a USB to HDMI cable)? I would also need to connect an external keyboard and mouse, so I plan on getting a USB hub to extend the second USB port on my Air. Will this setup work? I remember reading an article which said that the MBA can power only 1 external monitor. Is there any truth to this?

  • We need to know which MacBook Air. Some can support 2 displays, daisy-chained over Thunderbolt; some a single display. I don't know of any data on USB/HDMI though I'd doubt USB is fast enough.
    – Tetsujin
    Commented Apr 13, 2016 at 16:42
  • @Tetsujin Oh, it's the latest (2015) model. Question edited. Commented Apr 13, 2016 at 17:00
  • It really depends on what software and USB adapter you chose. OS X can handle dozens of displays and the limitations are almost always either physical port and performance needs. Can you perhaps explain what "work" means in terms of performance (200x300 resolution in 256 color depth with 2 Hz refresh rate is a different beast than HDMI 1.4). Is it for a kiosk that changes images once every 5 minutes or less or gaming? Good work on the edit to specify your hardware year.
    – bmike
    Commented Apr 13, 2016 at 17:38

2 Answers 2


The MBA GPU may be limited to a single external monitor, but the USB to HDMI requires a driver installed on the MBA and that video/image is not using the GPU, it's using the CPU. So the limit is bypassed. Now it might be more complicated than this, but I think is this the basic premise. Be aware that for fast moving videos or games the USB connected display may disappoint. Also if the MBA is running near 100% CPU usage and then you add this USB display it may also disappoint. If you looked to add more screen for email, YouTube it's likely to be fine. The hub might be more of an issue, if the cable is USB 3 make sure the hubs too


Yes and yes. Its GPU has limit of only one external monitor. But USB to HDMI adapters have its own simple GPU so you will need a driver installation. Main con is very limited resolution and screen refresh rate. Check adapter spec.

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