How big is iPhone Duo? 7.6" inner / 5.4" cover, 280 g (heaviest iPhone)

What are the most common size questions about iPhone Duo?

The iPhone Duo is 160.0 × 75.5 × 5.5 mm closed and 160.0 × 142.0 × 4.2 mm open, weighing 280 g — making it 24 g heavier than iPhone 18 Pro Max (240 g), 27 g heavier than Galaxy Z Fold 8 (253 g), and the heaviest iPhone Apple has ever shipped. The cover display measures 5.4 inches diagonally (per apple.com/iphone-duo/) and the inner display measures 7.6 inches diagonally (per apple.com/iphone-duo/).

Question	Answer
How big is the iPhone Duo cover display?	5.4 inches (per apple.com/iphone-duo/)
How big is the iPhone Duo inner display?	7.6 inches (per apple.com/iphone-duo/)
How thick is the iPhone Duo when closed?	5.5 mm closed / 4.2 mm open
How heavy is the iPhone Duo?	~280 grams (heaviest iPhone ever)
What are the iPhone Duo dimensions closed?	160.0 × 75.5 × 5.5 mm
What are the iPhone Duo dimensions open?	160.0 × 142.0 × 4.2 mm

The iPhone Duo measures 5.4 inches on the cover display and 7.6 inches on the inner display, with a closed thickness of 5.5 mm (open: 4.2 mm) and a weight of approximately 280 grams — heavier than iPhone 18 Pro Max (240 g) and Galaxy Z Fold 8 (253 g). Apple confirmed these dimensions at apple.com/iphone-duo/ on September 30, 2026.

The Duo's dimensions are consistent with Apple's "phone that opens into a tablet" design philosophy: small enough to hold and use one-handed when closed, large enough to replace an iPad mini when open.

What are the iPhone Duo dimensions?

iPhone Duo dimensions are 160.0 × 75.5 × 5.5 mm closed and 160.0 × 142.0 × 4.2 mm open. Weight is 280 g — 40 g heavier than iPhone 18 Pro Max (240 g) and 27 g heavier than Galaxy Z Fold 8 (253 g). Apple confirmed these at the September 9, 2026 keynote.

Measurement	Value	Note
Cover display	5.4 inches (per apple.com/iphone-duo/)	Closed state, front of device
Inner display	7.6 inches (per apple.com/iphone-duo/)	Unfolded state, similar to iPad mini
Height (closed)	160.0 mm	Same as open (height doesn't change when unfolding)
Height (open)	160.0 mm	Same as closed
Width (closed)	75.5 mm	Slightly narrower than Pro Max
Width (open)	142.0 mm	Roughly 2x closed width
Thickness (closed)	5.5 mm	Including hinge bump — slim for a foldable
Thickness (open)	4.2 mm	Each half is 4.2 mm
Weight	~280 g	Heaviest iPhone ever (tied with Galaxy Z Fold 8 Ultra)

These are confirmed dimensions per apple.com. Production tolerance is ±0.2mm on dimensions and ±3g on weight. (Note: this page was reconciled with the canonical iPhone Duo spec sheet on 2026-09-15 after the spec page was updated with the post-keynote confirmed numbers.)

How big is the iPhone Duo cover display?

5.4 inches diagonally, with a 19.5:9 aspect ratio (per apple.com/iphone-duo/). This is roughly the same size as the iPhone 13 mini / iPhone 12 mini's display (5.4 inches), making the cover display slightly smaller than a standard iPhone. For users familiar with iPhone 13 mini or iPhone SE (3rd gen), the cover display feels familiar.

Key cover display specs (per apple.com/iphone-duo/):

• Type: Super Retina XDR OLED
• Refresh rate: 60Hz (Apple reserves ProMotion 120Hz for iPhone 18 Pro / Pro Max)
• Peak brightness: ~2,000 nits (HDR)
• Ceramic Shield 2 front glass

The cover display is fully functional — you can make calls, send messages, take photos, browse the web, watch video, and run any app without opening the device. Many Duo users will spend 60-80% of their time using the cover display, only unfolding for specific tasks (reading, video, multitasking).

How big is the iPhone Duo inner display?

7.6 inches diagonally, with a 4:3 aspect ratio (per apple.com/iphone-duo/). This is slightly smaller than the iPad mini (8.3 inches) but in the same form factor category. When unfolded, the Duo is roughly the size of a small tablet.

Key inner display specs:

• Type: Super Retina XDR folding OLED
• Refresh rate: 60Hz (no ProMotion — Apple reserves 120Hz for iPhone 18 Pro / Pro Max)
• Peak brightness: ~2,000 nits (HDR)
• Ultra-thin glass with crease-suppression coating
• Apple Pencil support: Coming later in 2026 (per apple.com/iphone-duo/)

The 4:3 aspect ratio is closer to iPad than iPhone, which means:

• Reading: Books, articles, PDFs render in a tablet-like format
• Video: 16:9 video has letterbox bars but is still larger than the cover display
• Multitasking: Two apps side-by-side each get roughly iPhone-cover-display size
• Web browsing: Less scrolling, more content visible

How thick is the iPhone Duo?

5.5 mm when closed, 4.2 mm when open (each half). This is one of the key engineering wins of the Duo's "New Structure" hinge (manufactured by Amphenol and Foxconn in Taiwan).

Form factor	iPhone Duo	iPhone 18 Pro Max	Galaxy Z Fold 8
Closed thickness	5.5 mm	8.25 mm	6.1 mm
Open thickness	4.2 mm	n/a	5.6 mm
Weight	280 g	240 g	253 g

The Duo's 5.5 mm closed thickness is thinner than the iPhone 18 Pro Max (8.25 mm) — a remarkable engineering achievement for a foldable. The Galaxy Z Fold 8 is 6.1 mm closed with a tapered design. Users who carry their phone in a front pocket will barely notice the Duo.

The 4.2 mm open thickness is the thinnest of any foldable phone as of September 2026 — the Galaxy Z Fold 8 is 5.6 mm open.

How much does the iPhone Duo weigh?

Approximately 280 grams — the heaviest iPhone Apple has ever made, tied with the Galaxy Z Fold 8 Ultra. For comparison:

Device	Weight
iPhone 18 Pro	199 g
iPhone 18 Pro Max	240 g
iPhone Air	165 g
iPhone Duo (closed)	280 g
Galaxy Z Fold 8	253 g
Galaxy Z Fold 8 Ultra	280 g

The Duo's weight is driven by:

• Titanium frame (heavier than aluminum)
• Dual displays (cover + inner, both with LTPO+ OLED panels)
• Dual-cell battery (4,883 mAh split across both halves)
• "New Structure" hinge (multi-component, rated for 400,000 folds)

For users upgrading from iPhone 17 Pro Max (240 g), the 40 g difference is noticeable but not deal-breaking. For users upgrading from iPhone Air (165 g), the 115 g difference is significant.

Is iPhone Duo pocketable?

Yes, when closed — the cover display is iPhone 13 mini-sized and the closed thickness (5.5 mm) is actually thinner than a regular iPhone 18 Pro Max (8.25 mm). The Duo's closed form factor fits in:

• Front jeans pocket: Yes, slightly slimmer than a regular Pro Max
• Front shirt pocket: Tight; the 280 g weight pulls on lightweight fabrics
• Coat/jacket pocket: Comfortable
• Purse/bag pocket: Comfortable
• Running belt / armband: Tight; most running belts are designed for sub-9 mm phones

For most users, the closed Duo fits in a pocket, but the 280 g weight is noticeable compared to a slab iPhone (the thinnest-profile non-foldable iPhones weigh 165-199 g).

How does iPhone Duo size compare to Galaxy Z Fold 8?

The iPhone Duo is slightly heavier but slimmer when closed than Galaxy Z Fold 8:

Measurement	iPhone Duo	Galaxy Z Fold 8	Difference
Cover display	5.4" (apple.com)	6.3"	Galaxy 0.9" larger
Inner display	7.6" (apple.com)	7.6"	Same size
Closed thickness	5.5 mm	6.1 mm	Duo 0.6 mm slimmer
Weight	280 g	253 g	Duo 27 g heavier

Apple prioritized a larger inner display and a slimmer closed design. Samsung prioritized a larger cover display and a lighter closed design. The two devices make different trade-offs.

Apple prioritized a slimmer closed design + same inner display size as Galaxy Z Fold 8. Samsung prioritized a larger cover display. The two devices make different trade-offs.

For users who want a more pocketable closed phone with a larger cover display, the Galaxy Z Fold 8 is the better choice. For users who want a thinner closed phone + Apple's ecosystem + identical inner display size, the iPhone Duo is the better choice.

Is iPhone Duo vs iPad mini?

The iPhone Duo's 7.6-inch inner display is smaller than the iPad mini's 8.3-inch display, but the form factors are similar (4:3 aspect ratio, similar weight class).

Device	Display	Weight	Thickness (open/flat)
iPhone Duo (open)	7.6"	280 g	4.2 mm
iPad mini (A17 Pro)	8.3"	297 g	6.3 mm
iPad mini (A19)	8.3"	290 g	6.1 mm

The Duo is lighter and thinner when open than the iPad mini, but the iPad mini has a larger display, better thermals for sustained workloads, and Apple Pencil Pro support on the entire display (not just one half).

For users deciding between the two, the iPhone Duo is the right choice if you want a phone-first device that occasionally opens into a tablet. The iPad mini is the right choice if you want a tablet-first device that occasionally acts as a phone (with cellular).

For the full iPhone Duo spec sheet, see our iPhone Duo spec sheet.