iPhone Duo Screen Size

iPhone Duo Screen Size: 7.6-Inch Inner, 5.4-Inch Outer, and What It Means for Your Website

The iPhone Duo has two screens: a 7.6-inch inner display that you see when the phone is open, and a 5.4-inch outer display that you use when it is folded shut. Apple’s own tech specs list the exact diagonals as 7.58 inches and 5.36 inches when measured as a standard rectangle.

That is the short answer. But if you build websites or storefronts, the diagonal is the least interesting number on the spec sheet. The shape of these screens is unlike any iPhone that has come before, and that is the part worth twenty minutes of your attention.

Quick answer about iPhone Duo Screen Size

• Inner display: 7.6 inches, 1878 × 2670 pixels, 430 ppi
• Outer display: 5.4 inches, 1398 × 2034 pixels, 460 ppi
• Both: Super Retina XDR OLED, ProMotion up to 120Hz, 3,000 nits peak outdoor brightness
• Announced: September 9, 2026 — on sale October 23, from $1,999

iPhone Duo screen size at a glance

Apple announced the iPhone Duo on September 9, 2026, alongside the iPhone 18 Pro and Pro Max. It is the first foldable iPhone and carries the largest display Apple has ever put on a phone.

The device measures roughly 6.48 × 4.64 inches when open at 5.2mm thick, folding to 11.3mm. At 254 grams it is also the heaviest iPhone Apple has shipped.

The 5.4-inch outer display

The cover screen is the one you will actually use most, because iPhone Duo Screen Size is what you see every time you do not open the phone.

At 5.4 inches it sounds small — the same diagonal as the discontinued iPhone mini. But Apple claims that it delivers more than 90% of the screen area of the 6.3-inch iPhone 18 Pro, because it is a much wider, squarer rectangle rather than a tall thin one. It also runs at 460 ppi, the same density as the rest of the current lineup, and higher than the folding panel inside.

Apple positions the closed device as roughly passport-sized and comfortably one-handed, which is a genuine pitch to people who miss smaller phones.

The 7.6-inch inner display

Unfold it, and you get 7.6 inches of Super Retina XDR OLED — around the footprint of an iPad mini, and by Apple’s measurement about 50% more screen area than an iPhone 18 Pro Max.

Two things set this panel apart from the folding competition:

Density. At 430 ppi, it is the highest pixel density of any folding screen currently on sale. For comparison, the Galaxy Z Fold 8 sits at 404 ppi and the Pixel 10 Pro Fold at 374 ppi.

Finish. Apple applied a nano-texture matte layer — the same idea used on the Pro Display XDR — to scatter reflections instead of bouncing them back. A useful side effect is that it makes the crease harder to see. Apple has not claimed the crease is gone, only that it is less visible.

The inner display is also wide enough for iOS 27’s Split View, which runs two apps side by side. That is the first time an iPhone has done real side-by-side multitasking.

Why the aspect ratio matters more than the inches

Here is the detail most spec round-ups skip.

Every iPhone you have designed for in the last eight years has been a tall 19.5:9 rectangle — roughly 1:2.17. The iPhone Duo’s inner display is about 1:1.42, which is nearly the proportion of A4 paper. The outer display is about 1:1.45.

Two consequences fall out of that:

• The inner screen is not just a bigger phone. It is a small tablet in portrait and, in landscape, wider and shorter than anything in your existing breakpoint set.
• The outer screen is not a small phone. It is wider and considerably shorter than an iPhone 18 Pro — a shape no shipping iPhone has ever had.

Apple’s design decision to keep both panels at nearly the same ratio — a difference of roughly 2.3%, against about 20.8% between the Galaxy Z Fold 8’s two screens — is what makes content scale cleanly when the phone opens and closes. For you, that means one layout that works at two sizes, rather than two different layouts.

What the iPhone Duo Screen Size means for web developers

Nothing breaks on October 23. Responsive sites will render. But a few things are worth doing before your clients start opening their sites on one of these.

1. Check your widest phone breakpoint. If your theme jumps from a 428px phone layout straight to a 768px tablet layout, the Duo’s inner display lands in the awkward middle. A layout tuned for a narrow column will look stretched and empty on a squarer screen.

2. Stop assuming portrait means narrow. A lot of WordPress themes hide navigation, stack columns and shrink hero text based on portrait orientation alone. On a screen that is 1.42:1, that logic produces a page designed for a phone shown on something the size of an iPad mini.

3. Use container queries where you can. Component-level sizing handles a device that changes shape mid-session far better than viewport media queries do. This is exactly the case container queries were designed for.

4. Expect resize events mid-session. Unfolding changes the viewport while your page is open. Sliders, sticky headers, canvas elements and anything that measures dimensions once on load should be recalculating on resize.

5. Do not hard-code point values yet. Apple has published pixel resolutions and densities but not the CSS point dimensions. The figures circulating online — roughly 626 × 890 points inside and 466 × 678 outside — are calculated from a 3x scale factor, not published specs. Treat them as an estimate until Apple’s developer documentation catches up.

This is the same lesson the ecosystem keeps re-learning: build against flexible systems rather than device-specific numbers. We made a similar point about dependency hygiene in our write-up on Shopify’s acquisition of Tailwind Labs — the tooling changes underneath you, so keep your layout decisions in one place.

iPhone Duo vs iPhone 18 Pro Max vs Galaxy Z Fold 8

The inner Duo panel is the only iPhone screen Apple lists below 460 ppi. In raw pixel count it still wins comfortably: about 5.0 million against roughly 3.8 million on the Pro Max.

Price and availability

The iPhone Duo starts at $1,999 for the 256GB model, with 512GB, 1TB and 2TB options above it. Pre-orders open October 16, with sales beginning October 23. Full figures are on Apple’s iPhone Duo tech specs page and in the Apple Newsroom announcement.