Apple's new foldable iPhone Duo can display two apps at once on its inner screen, but the feature works differently than the Split View multitasking tool longtime iPad owners already know. Rather than letting users drag a divider to adjust how much space each app gets, the iPhone Duo locks the layout into a fixed 50/50 split.

No resizing, even in landscape

Apple's marketing for the iPhone Duo highlights app pairs and side-by-side windows, but it stops short of mentioning any ability to resize those windows. That's because there isn't one. Every side-by-side pairing on the device's 7.6-inch foldable display divides the screen evenly between the two apps, with no option to give one app more room than the other.

That stands in contrast to the iPad, where Split View has allowed users to drag the boundary between two apps in landscape mode since Apple introduced the feature with iOS 9 back in 2015. iPad owners accustomed to that flexibility may be surprised to find the iPhone Duo doesn't offer the same control.

Why Apple locked the split at 50/50

The rigid split appears to be a consequence of the iPhone Duo's screen dimensions rather than a simple software limitation. Both the inner and outer displays share the same 1:1.4 aspect ratio, and each half of the inner display, when split down the middle, ends up roughly matching the shape of the outer screen. That means a straight 50/50 division lets each app run in a canvas its layout already supports, with the divide falling neatly along the device's fold.

Allowing users to drag that boundary would introduce a wide range of in-between window sizes that wouldn't align with the outer display's dimensions. It would also complicate things significantly for developers, who would need to build support for many more layout possibilities into their iPhone apps rather than a single, predictable split-screen size.

One apparent exception involves video playback in portrait mode. Based on Apple's own promotional videos, content like an Apple TV show or movie shown above another app can appear in its native aspect ratio, with the app running underneath extending upward past the fold.

Still useful multitasking, just not customizable

Even without resizing, the iPhone Duo's side-by-side mode offers real multitasking benefits. Users can quickly switch between two open apps, run two windows of the same app simultaneously, or keep a Messages conversation open while viewing content in another app, whether the device is held in portrait or landscape orientation. Apple also lets users save specific app pairings to return to later.

The limitation was highlighted publicly by a user posting on X under the handle @planetofgori, who shared a video demonstrating that split-screen app sizes on the iPhone Duo cannot be adjusted and are locked to a 1:1 ratio.

Availability and pricing

As Apple's first iPhone with a foldable display, the iPhone Duo was always expected to come with some adjustment for users, particularly those switching over from the iPad's more flexible multitasking tools. The device starts at $1,999. Pre-orders are set to begin Friday, October 16, with availability starting Friday, October 23.