Apple says the new iPhone Duo is the thinnest iPhone ever when unfolded, measuring 5.2mm — 0.4mm thinner than the 5.6mm iPhone Air.
Rumors had suggested the device might reach 4.5mm when unfolded, matching the Galaxy Z Fold8, but the final unfolded thickness is 5.2mm. At that thickness it remains slightly thicker than Apple’s thinnest device overall, the 13-inch iPad Pro at 5.1mm.
iPhone Duo dimensions and weight
When folded, the iPhone Duo is 11.3mm thick. By comparison, the iPhone 17 Pro Max and iPhone 18 Pro Max are both 8.75mm thick. The iPhone Duo is also Apple’s heaviest iPhone to date at 254 grams, five grams heavier than the 249-gram iPhone 18 Pro Max.
Displays, design and availability
The device offers a 7.6-inch inner display when open and a 5.4-inch outer display when closed, and Apple describes its proportions as short and wide. Pre-orders for the iPhone Duo begin on October 16 ahead of an October 23 launch date.

