The iPhone Duo has officially entered Apple’s lineup with a design that changes its physical size when it moves between folded and open positions. Apple unveiled the foldable iPhone on September 9, 2026, confirming dimensions of 6.48 inches wide, 4.64 inches tall and 0.21 inch thick when open. Folded, it measures 3.31 inches wide, 4.64 inches tall and 0.44 inch thick.
Those measurements make the new model very different from a conventional iPhone. Instead of keeping one fixed rectangular shape, the device becomes a compact, passport-like phone when closed and a much larger screen when opened.
Apple lists the weight at 8.96 ounces, or 254 grams. The company also confirms a 7.6-inch inner OLED display and a 5.4-inch outer display. The phone will be available in the United States beginning October 23, 2026, with preorders scheduled to begin October 16.
iPhone Duo Size at a Glance
The physical specifications are easiest to understand by separating the two configurations.
| Specification | Open | Folded |
|---|---|---|
| Width | 6.48 inches | 3.31 inches |
| Height | 4.64 inches | 4.64 inches |
| Thickness | 0.21 inch | 0.44 inch |
| Width | 164.6 mm | 84.1 mm |
| Height | 117.8 mm | 117.8 mm |
| Thickness | 5.2 mm | 11.3 mm |
| Weight | 8.96 ounces | 8.96 ounces |
| Display | 7.6 inches | 5.4 inches |
The height stays exactly the same in both positions. The major change happens across the width.
When the phone opens, the width increases from 3.31 inches to 6.48 inches. At the same time, the body becomes much thinner, moving from 0.44 inch folded to 0.21 inch open.
That transformation is central to the design.
How Big Is the iPhone Duo When Open?
The open configuration measures 6.48 inches across and 4.64 inches high. Apple lists the depth at 5.2 mm, making the open device 0.21 inch thick.
This is the configuration that exposes the phone’s 7.6-inch inner display. Apple describes it as the largest display ever placed on an iPhone.
The large screen is designed for viewing content, gaming and multitasking. It also supports Apple Pencil through USB-C, with that capability arriving later in 2026.
The 7.6-inch screen has a resolution of 1878 by 2670 pixels and a density of 430 pixels per inch. It uses OLED technology and includes a nano-texture finish designed to reduce glare and reflections.
The physical dimensions therefore support a very different experience from a standard smartphone. Users can move from a compact phone to a much larger workspace without carrying a separate tablet-sized device.
How Big Is the iPhone Duo When Folded?
When closed, the device measures 3.31 inches wide, 4.64 inches high and 0.44 inch thick.
Apple compares the closed form to the size of a passport. The 5.4-inch outer display remains available while the device is folded, allowing users to handle everyday smartphone tasks without opening the phone.
The folded width is less than half the open width. That makes the closed configuration considerably narrower than the full device.
The 11.3 mm folded thickness is also important. Folding two sections together naturally creates a thicker body, and Apple’s design places the internal components across both sides of the device.
For anyone focused on portability, the folded measurements are likely to be the most relevant numbers.
Why the Width Changes So Much
The Duo’s folding mechanism works along the center of the device.
When open, both halves sit side by side and form the large internal screen. When closed, those halves come together.
That is why the width changes from 84.1 mm to 164.6 mm.
The height does not change because the hinge folds the device across its width rather than shortening the overall vertical dimension.
This creates a distinctive shape in each position:
- Closed: 84.1 mm wide by 117.8 mm tall
- Open: 164.6 mm wide by 117.8 mm tall
The difference is substantial enough that the Duo effectively has two physical profiles.
The 7.6-Inch Inner Screen
The inner display is the main reason the Duo becomes so much larger when opened.
Apple says the 7.6-inch display provides 50 percent more screen area than the iPhone 18 Pro Max. It is also 80 percent larger than the display on the iPhone 18 Pro.
The panel supports ProMotion with adaptive refresh rates of up to 120Hz. It also supports Always-On functionality, HDR, True Tone, P3 wide color and up to 3,000 nits of outdoor peak brightness.
The display uses a nano-texture finish that reduces reflections. Apple has also designed the display layers to manage the stresses created when the panel bends repeatedly.
The company says the nano-textured cover layer uses a custom polymer with up to 40 percent higher stiffness than other materials used in the industry.
These details matter because the display dimensions cannot be separated from the folding mechanism. The large screen must remain usable while repeatedly changing shape.
The 5.4-Inch Outer Screen
The outer display measures 5.4 inches diagonally.
Apple lists its resolution at 1398 by 2034 pixels and its pixel density at 460 ppi.
The company says the outer screen provides 90 percent of the screen area of the iPhone 18 Pro. It also supports ProMotion, Always-On functionality and up to 3,000 nits of outdoor peak brightness.
The outer display means users do not need to open the phone for every interaction.
That is an important part of the physical design. The folded Duo remains a functioning smartphone rather than becoming a device that requires opening for most tasks.
The Open Thickness Is One of the Biggest Design Features
At 5.2 mm, the Duo is extremely thin when opened.
Apple calls it the thinnest iPhone ever in its open configuration.
That figure becomes 11.3 mm when the phone is closed. The difference is more than 6 mm.
The thickness figures also show why comparing the Duo with a traditional iPhone using only one measurement can be misleading.
A regular iPhone has one primary body thickness. The Duo has two practical thickness measurements because its structure changes.
The 5.2 mm figure describes the open body. The 11.3 mm figure describes the folded device.
The Weight Remains 254 Grams
Apple lists the Duo at 254 grams, equivalent to 8.96 ounces.
The weight remains the same regardless of whether the phone is open or closed. Folding the device changes its shape but does not remove or add components.
The weight reflects the hardware required for the folding system, two displays, batteries, cameras and titanium enclosure.
For buyers comparing physical size, weight is therefore another important specification.
The Duo combines a large 7.6-inch display with a relatively compact folded footprint, but the hardware required to deliver that design contributes to its 254-gram weight.
The Hinge Determines the Physical Form
The precision hinge is one of the most important components behind the dimensions.
Apple says the hinge contains more than 100 components. It supports the center of the display when the phone is fully open and works with an integrated magnet array to provide a secure closure.
The hinge allows the two halves to move smoothly between the two configurations.
Apple has also built internal support ribs into the structure to increase stiffness. Ceramic fiber inserts are used around antenna splits to reinforce the frame.
The result is a design that has to remain thin while also supporting a large folding display.
Titanium Construction Adds to the Structural Design
The Duo uses Grade 5 titanium for its enclosure.
Apple gives the frame a polished finish and uses a contrasting micro-blasted treatment on the 3D-printed hinge cover.
The rear receives Ceramic Shield protection, while the front uses Ceramic Shield 2.
Apple also gives the Duo an IP68 rating for splash, water and dust resistance.
These materials are relevant to the dimensions because a foldable phone needs structural rigidity across a body that repeatedly changes shape.
The Display Measurements Are Not the Same as the Body Measurements
It is important to distinguish screen size from device size.
The inner display is advertised as 7.6 inches diagonally, while the physical body is 6.48 inches wide and 4.64 inches tall when open.
Likewise, the outer screen measures 5.4 inches diagonally, while the folded body measures 3.31 inches wide and 4.64 inches tall.
Apple notes that the rounded corners affect the actual screen area. When measured as standard rectangles, the displays measure 7.58 inches and 5.36 inches diagonally.
That distinction is common with modern smartphone displays and prevents the diagonal measurement from being confused with the actual physical width or height.
How the Two Configurations Affect Everyday Handling
The folded configuration is the smaller form.
Its 3.31-inch width makes it considerably narrower than the open body. Apple designed the outer display for regular smartphone interaction, while the larger inner display provides additional room when users need it.
Opening the phone changes the width dramatically.
The device goes from 84.1 mm wide to 164.6 mm wide. The height remains 117.8 mm.
That means the Duo does not simply become a larger version of the same phone. It changes into a different physical format.
This is especially relevant for multitasking. Apple has redesigned iOS 27 for the folding form, allowing applications to work side by side and adapting the interface to different orientations.
iPhone Duo Dimensions and Portability
Portability is one of the biggest reasons the dimensions matter.
Folded, the Duo is compact enough for the pocket while retaining a usable 5.4-inch display.
Open, it becomes a much wider device with a 7.6-inch screen.
That combination gives the phone two distinct roles. The closed configuration focuses on convenience, while the open configuration focuses on screen space.
The 0.44-inch folded thickness is the main physical compromise.
Once open, the body becomes only 0.21 inch thick. That makes the transition particularly noticeable when handling the phone.
How the Dimensions Relate to the Camera System
The Duo includes a 48MP Dual Fusion camera system.
Apple designed the camera system around the foldable body. The folding format also enables camera features that use both displays.
Users can use the outer screen as a preview when taking photos with the main cameras. The design also supports new ways to position the phone for hands-free photography and FaceTime.
The camera hardware creates a raised section on the back, so the published 0.21-inch and 0.44-inch measurements should be understood as the primary body dimensions rather than a uniform thickness across every exterior surface.
Colors and Storage Do Not Change the Size
Apple offers the Duo in Star White and Night Sky.
Storage options range from 256GB to 2TB.
The storage capacity and color do not change the published dimensions.
That means buyers can choose between configurations without worrying about one version being physically larger.
The base model starts at $1,999 in the United States with 256GB of storage. The highest-capacity version reaches $3,199 with 2TB.
The dimensions remain consistent across the lineup.
U.S. Release Timing
Apple introduced the Duo on September 9, 2026.
U.S. preorders begin October 16. Retail availability begins October 23.
That gives consumers several weeks between the official announcement and the first day of availability.
By announcing the exact measurements ahead of release, Apple has given prospective buyers enough information to assess the physical format before purchasing.
The most important numbers remain simple: 3.31 inches wide when folded, 6.48 inches wide when open, and 5.2 mm thick when open.
What Makes the Size Different From a Traditional iPhone
The biggest difference is flexibility.
A traditional iPhone remains the same shape whether it is being used for a quick message, video viewing or multitasking.
The Duo changes physical size according to the task.
The 5.4-inch outer display handles the folded experience. The 7.6-inch inner display provides a substantially larger workspace when opened.
The 254-gram weight stays constant, but the dimensions change.
That combination makes the physical design the defining feature of the device.
Final Take on the Size
The confirmed measurements give a clear picture of Apple’s approach to its first foldable iPhone.
Open, the Duo measures 6.48 inches wide, 4.64 inches tall and 0.21 inch thick. Folded, it measures 3.31 inches wide, 4.64 inches tall and 0.44 inch thick.
The device weighs 8.96 ounces and includes a 7.6-inch internal display alongside a 5.4-inch external screen.
For U.S. buyers, the most important consideration is how those measurements change during everyday use. The Duo can function as a narrower phone when closed and become a large-screen device when opened.
Its dimensions also explain Apple’s emphasis on portability. The company has designed a phone that can offer a much larger display without requiring users to carry a permanently large device.
The iPhone Duo therefore introduces a new physical format to Apple’s smartphone lineup, with the hinge, displays and thin titanium body all working together around the same central idea: a compact phone that can open into a much larger screen.
What do you think about the iPhone Duo’s size and foldable design? Share your thoughts and stay tuned for the latest updates as its U.S. launch approaches.