CommandDeskGuide
Sidecar for Windows: use your PC as a second screen for your Mac
Sidecar turns an iPad into a second screen for a Mac, but it doesn't work with anything else. If there's a Windows laptop, a Surface or an Ubuntu PC on your desk, it can do the same job. Here's how. We make CommandDesk, one of the apps below, so other products are described from their own pages.
1.Why Sidecar and a cable won't do it
Apple's Sidecar only works with an iPad signed in to the same Apple Account as your Mac. And a cable won't help either: a laptop's HDMI port only sends video out, so plugging your Mac into it shows nothing. The picture has to come over your network, through an app on both computers.
2.Use your PC as a second screen with CommandDesk
- Install CommandDesk on your Mac and the free CommandDesk app on your Windows or Ubuntu PC.
- Your PC appears in CommandDesk. Pair it once: both screens show the same 6-digit code.
- From the CommandDesk menu, choose Use [your PC] as a Second Screen. Your Mac adds a display and the PC shows it full screen.
- Drag windows onto it like any monitor, and pick in the menu whether the PC sits left or right of your Mac.
The second screen runs at your PC screen's own resolution, so text is sharp. The pointer is drawn right on the PC, so it moves smoothly, and on a touchscreen like a Surface you can tap, drag and scroll with two fingers.
The same app also lets your Mac's keyboard and mouse control the PC when you're not using it as a screen, with copy and paste between them. One PC at a time; $19 once.
Turn your PC into a second screen for your Mac
Windows 10/11 or Ubuntu, sharp at full resolution, touch works on a Surface. $19 once, refund if it can't connect.
3.Duet Display
Duet's app can use a Mac, a PC, an iPad, an iPhone or an Android device as a second display, with an account signed in on both. It's a subscription with paid Air and Pro plans; check Duet's plans page for current prices and which plan you need for using a computer as the display.
Best for: using phones and tablets as screens too, if a subscription suits you.
Side by side
| Sidecar | CommandDesk | Duet | |
|---|---|---|---|
| Second screen can be | An iPad | A Windows 10/11 or Ubuntu PC | A Mac, PC, iPad, iPhone or Android device |
| Price | Free, built into macOS | $19 once (also shares keyboard and mouse) | Subscription (paid Air and Pro plans) |
| Account needed | Same Apple Account on both | No, pair with a 6-digit code | Duet account on both |
From Apple's and Duet's own pages, October 2026.
Questions
Is there a Sidecar for Windows?
Not from Apple: Sidecar only works with an iPad. To use a Windows PC as a second screen for a Mac you need an app on both computers, such as CommandDesk or Duet.
Can I connect my Mac to my laptop with an HDMI cable and use it as a monitor?
Almost never. A laptop’s HDMI port sends video out, it doesn’t take it in, so plugging a Mac into it shows nothing. The second screen has to come over your network or a USB connection, through an app.
Can I use a Surface as a second screen for my Mac?
Yes. A Surface is a Windows PC, so CommandDesk works with it, and its touchscreen works too: tap to click, drag, and scroll with two fingers on the Mac’s second screen.
Does it work with an Ubuntu laptop?
With CommandDesk, yes: Ubuntu or another Linux with the GNOME desktop.
Is it good enough for video or games?
It’s made for working: documents, chat, a browser, a live chart. The picture travels over your network, so it suits work rather than fast games, and it’s smoothest on a wired network or 5 GHz Wi-Fi.
Also want one keyboard and mouse for both? Compare the keyboard and mouse sharing apps for Mac.
CommandDesk: one keyboard and mouse for your Mac and PC
Plus a second screen and your PC's sound on your Mac. $19 once, with a refund if it can't connect to your PC.