Phone, tablet or laptop as a second monitor with Spacedesk

There's a free app called "spacedesk" that turns a "secondary machine" into a second monitor. Your main computer has to run on Windows, but the secondary device can be an Android, a Windows or a Mac one. Both machines must be on the same LAN. All info is on

I have one monitor only and really missed being able to get a fullscreen preview. The tablet I tried as a secondary display has a 10" screen (only) and isn't 16:9. So getting a fullscreen preview on isn't very interesting, plus the colors are different than on my main monitor...

But, the trick is, I can get a fullscreen preview on my main display! I reduce HF's window, put it on the tablet, make it fullscreen again, THEN go to "options" and there "set screen" to my main monitor I could even do this with my phone (if I only had my phone). I tried. I had to use a magnifier, but it worked and I was able to get a full screen preview on my main monitor. Of course neither of these are a practical working set-up, but they do allow for a really full screen preview.

I also tried with a laptop I have. It's cheap and can't do much more than word processing. But it's screen is nice and makes a very decent secondary display I can send ther fullscreen preview to, or it can host the workspace so the full screen preview can be on my usual monitor. It's just that don't have enough room on my desk to make that a permanent solution.



  • Still an interesting product. How is that working? I'd be a little concerned the wifi transfer could cause display lag. 

  • There is a slight lag that's less visible when the main monitor is used for the fullscreen preview. It's also less perceptible when the other machine is connected via ethernet cables rather than wifi. That said, I haven't tried to tweak the settings that allow to sacrifice some color depth to increase speed (or the reverse).

    It's certainly not as confortable as a "real" secondary display directly plugged to the graphics card, but it can help get an idea of what the full screen video will look like, and when speed isn't an issue, like for color grading, or non-video work.

    I mean, it's free and works pretty well for the price ;)

  • Latest tests: I connected a tablet AND a phone to have two more displays

    Hint: the resolution of the secondary display doesn't have much to do with its actual resolution. It's more "how many pixels from the main source" are going to be transferred to it. For instance, I started by setting the resolution of my phone (ine the client app) to 1920x1080 becaue that's the physical resolution of its screen. I ended up having the same amount of information I have on my monitor, but on 1/25th of the surface!!!

    The app doesn't accept resolutions lower than 800x600. I wanted dimensions that had a 16:9 aspect ratio, so I looked for the smallest even (the app wants even numbers) multiple of 9 greater than 600 and that was 68x9 = 612, and the width had to be 68x16 = 1080. So I set the app on my phone to a 1080x612 resolution. I'm giving you this as an example.


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