How Split View works on iPhone Duo

iPhone Duo is the first iPhone that can run two apps side by side. Open the device in landscape, and the inner display can be shared between two apps — or two windows of the same app, such as two Safari windows for comparing prices.

How to open two apps

• With iPhone Duo open in landscape, swipe up from the bottom edge and pause, then drag an app to the left or right side and pick the second app.
• Or touch and hold an app icon, tap Open in Split View, then pick the second app.

Each side can be switched to a different app on its own. To go back to one app, drag the divider all the way to the left or right edge. Each app keeps its sidebar or tab bar on its own outer edge, so the app on the left has its controls on the left.

Every app takes part

Developers don’t have to opt in, and they can’t opt out: every app can be placed side by side on iPhone Duo. That includes apps that haven’t been updated yet — a letterboxed app simply has less space to waste when it only occupies half the screen.

What you can do with it

• Pair two apps. Put a document next to a chat, a map next to a booking, or a video next to notes.
• Save pairs. Tap the divider between two apps to pair them. Opening either app then opens both, and the pair shows up together in the App Switcher.
• Two windows of one app. Apps that support multiple windows, such as Mail, Notes, Safari and Files, can open a second window beside the first: tap the app’s icon again while you’re in Split View.
• Drag and drop. Move photos, text and files from one app to the other.
• Siri beside your content. Apple shows Siri open in one half of the screen next to Mail in the other.

What it can’t do

• Two apps at most. There’s no third app and no Slide Over. Only a Picture in Picture video can float on top.
• Always 50/50. The two apps share the screen equally; the divider doesn’t resize them.
• Landscape only. Turn the open phone to portrait and you’re back to one app. In portrait you can pin a video to the top and use another app below it: start the video, send it to Picture in Picture, open the other app, then tap the pin button on the video.
• Inner display only. Apple documents Split View for the open phone, and new windows can only be created on the inner display.
• No free-form windows. There’s no Stage Manager or resizable windows like on iPad.

How comfortable an app feels at half width depends on its layout — apps with iPad versions tend to cope best.

Good pairs to try

Chat assistants such as ChatGPT, Claude and Gemini are natural partners for almost anything. Productivity apps like Notion, Slack and Google Docs benefit from a reference open next to them. Each app page on WorksOnDuo notes when an app is especially good at half width.