How can I use my iPad as a portrait Sidecar display?

Create a portrait virtual desktop and stream its rotated image to the connected Sidecar display. BetterDisplay's virtual-screen creation dialog can configure both parts together. This requires Pro and Screen Recording permission. The portrait desktop comes from the virtual screen, while Sidecar carries its rotated image to the iPad.

  1. Connect the iPad through Sidecar so it appears as a display on the Mac. Start the Sidecar session with the iPad in landscape orientation.
  2. Open Settings > Displays > Overview > Create New Virtual Screen….
  3. Choose Match aspect ratio of and associate to a display, then select the Sidecar display in Display to match.
  4. Leave Associate the virtual screen with this display enabled and enable Configure full screen stream to this display.
  5. Under Rotation (portrait mode), choose Portrait 90° (Sidecar port down) or Portrait 270° (Sidecar port up) to match how you will physically position the iPad.
  6. Choose Create Virtual Screen. Check that the new virtual desktop is connected and streaming to the iPad, then select a comfortable HiDPI desktop size from the virtual screen's Display Mode menu if needed.

For the rendering background, see choosing a comfortable HiDPI desktop size.

If the rotation selector is unavailable because permission is missing, grant Screen Recording access in macOS System Settings and reopen the creation dialog. The virtual screen is the source, and the Sidecar display is the target. Check that they are selected in that order.

Keep the pointer on the virtual desktop

The virtual desktop and Sidecar target remain separate displays in the Mac's arrangement. Place the virtual desktop next to the display you work from, and move the Sidecar target toward a corner where you are less likely to enter it accidentally. Work on the virtual desktop, whose image is being shown on the iPad.

A pointer on the physical Sidecar target can appear unrotated over the streamed image. Use Command-click or Warp Mouse Cursor to reach the corresponding source position. Moving the target in the arrangement reduces accidental crossings, though its desktop remains connected.

You can also try the stream’s experimental Prevent Cursor Entering option. If it is hidden, hold Option while opening the streaming menu to reveal the advanced items. Streaming also does not establish Apple Pencil or touch-event forwarding into the rotated virtual desktop.

If the image turns sideways or is cut off

Check the virtual source's shape and the stream's rotation separately. The creation dialog configures both together. Rotating the stream again afterward can leave the source’s shape and the presented image mismatched.

Sidecar's iPad-side orientation can also interfere. Starting the session in landscape and locking the iPad's orientation there before physically rotating it can help. If its interface has already rotated unexpectedly, close the Sidecar app on the iPad and start the session again in landscape. This is a workaround, not a guarantee that every iPadOS session will retain the intended orientation. You may need to unlock rotation again for ordinary iPad use.

For a blank output, verify the selected source and target, capture permission and whether the stream is hidden. There is no single confirmed fix for every Sidecar black-screen or reconnection problem. See Create Virtual Screen and Streaming for the complete setup and presentation options.