iPhone Air is 5.64 mm thick and weighs 165 g; iPhone Duo is 5.2 mm thick open, 11.3 mm closed, and weighs 254 g, so the foldable is the thinner phone only while it is unfolded and it carries 89 g more. Both are titanium, both use a 2x crop of a 48MP main sensor instead of a telephoto lens, and the gap between them is $900 at every matching storage tier: $1,099 for the Air and $1,999 for the Duo at 256GB.
Every figure comes from Apple’s tech specs and Store pages. The Air launched at $999 in September 2025 and Apple’s Store page now lists it from $1,099; Apple has not explained the change, so we report it as shown.
Key facts
| Spec | iPhone Duo | iPhone Air |
|---|---|---|
| Price | $1,999 / $2,199 / $2,599 / $3,199 | $1,099 / $1,299 / $1,699 (256GB, 512GB, 1TB) |
| Weight | 254 g | 165 g |
| Thickness | 5.2 mm open; 11.3 mm closed | 5.64 mm |
| Displays | 7.6-inch inner, 430 ppi; 5.4-inch outer, 460 ppi | 6.5-inch, 2736 x 1260, 460 ppi |
| Chip | A20 Pro, 7-core GPU | A19 Pro, 5-core GPU |
| Rear cameras | 48MP main plus 48MP Ultra Wide | 48MP main only |
| Video playback | Up to 44 h outer, 31 h inner | Up to 27 h |
| USB-C | USB 3, 10 Gb/s, DisplayPort | USB 2, 480 Mb/s |
Thin vs folding: dimensions, weight and materials
The Air is 156.2 mm tall, 74.7 mm wide and 5.64 mm thick. Closed, the Duo is 117.8 mm tall, 84.1 mm wide and 11.3 mm thick: 38 mm shorter, 9 mm wider and exactly double the Air’s thickness. Open, it is 164.6 mm wide and 5.2 mm thick, 0.44 mm thinner than the Air. Apple calls the Duo ‘the thinnest iPhone’ on its product page, and the qualifier is that the claim applies to the open position.
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Both phones are titanium with Ceramic Shield 2 on the front and Ceramic Shield on the back, and both are 35 percent recycled material by weight. The Duo specifies a Grade 5 titanium frame with a mirror-polished finish and a hinge cover 3D-printed from 100 percent recycled titanium, and it is rated IP68 to 6 meters for 30 minutes. The Air’s IP rating was not in the spec rows we compiled, so we do not compare it.
Displays: 6.5 inches vs 7.6 and 5.4
The Air has a single 6.5-inch OLED at 2736 x 1260 and 460 ppi. The Duo’s outer display is 5.4 inches at 1398 x 2034, also 460 ppi, and its inner display is 7.6 inches at 1878 x 2670 and 430 ppi. Every panel runs ProMotion up to 120Hz and shares the same ratings: 1000 nits typical, 1600 peak HDR and 3000 outdoors.
The difference is shape. The Air is a tall slab; the Duo’s open display is a wide, passport-like format that Apple pairs with Split View in iOS 27, StandBy and layouts that respond to how the phone is posed. The inner panel is Always-On and has a nano-texture finish to cut glare and hide the crease.
Cameras: one lens vs two, and the shared 2x crop
On paper the main cameras are identical: both list a 48MP Fusion main at 26 mm and f/1.6 with sensor-shift OIS, both derive a 12MP 2x telephoto at 52 mm from it, and both stop at 10x digital zoom. The Duo adds a 48MP Ultra Wide at 13 mm and f/2.2 with a 120-degree field of view and 48MP macro, which the Air lacks.
| Camera | iPhone Duo | iPhone Air |
|---|---|---|
| Main | 48MP, 26 mm, f/1.6, sensor-shift OIS | 48MP, 26 mm, f/1.6, sensor-shift OIS |
| 2x | 12MP crop, 52 mm, f/1.6 | 12MP crop, 52 mm, f/1.6 |
| Ultra Wide | 48MP, 13 mm, f/2.2 | None |
| Optical zoom steps | 0.5x, 1x, 2x | 1x, 2x |
| Front | 12MP Center Stage f/2.2 outer; under-display f/1.8 inner | 18MP Center Stage, f/1.9 |
| Rear video | 4K Dolby Vision up to 120 fps; Dual Capture 4K 30 | 4K Dolby Vision up to 60 fps |
The Air has the higher-resolution selfie camera at 18MP. The Duo’s answer is that its rear cameras can face you while you frame on the outer display, which is what Smart Take, Duo Preview, Kid Cue and Duo FaceTime rely on; our iPhone Duo camera guide explains those four features.
Battery, ports and price
Apple rates the Air at up to 27 hours of video playback and 22 streamed, or 40 and 35 with the MagSafe Battery. The Duo’s dual batteries are rated at 44 hours of video and 37 streamed on the outer display, 31 and 26 on the inner display, and up to 24 hours of typical use. The Air charges to 50 percent in 30 minutes with a 20W adapter or a 30W adapter over MagSafe, with MagSafe and Qi2 capped at 20W; the Duo reaches 50 percent in about 20 minutes with a 60W adapter and takes MagSafe and Qi2 at 25W.
The Air’s USB-C port is USB 2 at 480 Mb/s; the Duo’s is USB 3 at 10 Gb/s with DisplayPort output. Both have Wi-Fi 7 and Bluetooth 6. The Air pairs Apple’s C1X modem with the N1 wireless chip; the Duo pairs the C2 with N1, adds Thread and two years of satellite features, and is eSIM only worldwide.
Apple’s Store page lists the Air at $1,099, $1,299 and $1,699 for 256GB, 512GB and 1TB, and the Duo at $1,999, $2,199 and $2,599 for the same tiers, plus $3,199 for a 2TB option the Air does not offer. The Duo can also be paid at $83.29 a month over 24 months or leased from $57.99 a month; Apple’s Trade In page values the Air at up to $585.
What Apple has not said
- The battery capacity in mAh or the RAM of either phone
- The Air’s audio playback hours and IP rating in the spec rows we compiled
- Whether the Duo’s 5.2 mm open thickness includes the camera plateau
- A hinge durability rating for the Duo
The Air is on sale now from $1,099. iPhone Duo pre-orders open Friday, October 16 at 5 a.m. PT and it ships Friday, October 23 from $1,999; see our iPhone Duo launch article for the full sheet. For a slab with a telephoto, the iPhone 18 Pro ships September 18 from $1,199, and the event recap lists everything else Apple announced.
