Upgrading to the iPhone 18 Pro? Almost all older cases will survive the jump because Apple kept its exterior dimensions identical to the iPhone 17 Pro.
Apple lists both generations of the smaller Pro at 5.91 inches tall, 2.83 inches wide, and 0.34 inch deep. In metric measurements, each phone is 150 mm by 71.9 mm by 8.75 mm.
The same applies to the larger models. Both iPhone 17 Pro Max and iPhone 18 Pro Max measure 6.43 inches tall, 3.07 inches wide, and 0.34 inch deep, or 163.4 mm by 78 mm by 8.75 mm.
- iPhone 17 Pro and iPhone 18 Pro measure 150 mm by 71.9 mm by 8.75 mm
- iPhone 17 Pro Max and iPhone 18 Pro Max measure 163.4 mm by 78 mm by 8.75 mm
Those measurements come directly from Apple's technical specifications and its support pages for iPhone 17 Pro and Pro Max. Unlike some annual updates, there isn't even a fraction-of-a-millimeter difference between the corresponding models.
The matching height, width, and depth confirm that an older case can wrap around the new chassis. Apple also retained the Action button, volume controls, side button, Camera Control, USB-C port, and full-width camera platform introduced with the iPhone 17 Pro.
The new models do bring substantial internal and camera changes. The iPhone 18 Pro adds the A20 Pro chip, redesigned cooling, and a 48MP main camera with variable aperture, but Apple fit those upgrades inside the existing exterior dimensions.
Apple hasn't formally promised that cases are interchangeable, however. Its new silicone and TechWoven case listings identify only iPhone 18 Pro or iPhone 18 Pro Max under compatibility, while the older cases continue to list only their matching iPhone 17 model.
Apple's identical measurements make the cases physically compatible, but the company hasn't certified them for cross-generation use. It sells separate case SKUs for the new phones instead of listing both generations as compatible.
Before the event, OtterBox provided another strong indication that the cases would be reusable. Packaging spotted at Best Buy identified one case as compatible with both iPhone 17 Pro and iPhone 18 Pro, although our earlier warning recommended waiting for Apple's final specifications.
Check specialized cases before reusing them
Most conventional silicone, plastic, and leather cases with a broad opening around the camera platform should fit normally. The matching chassis measurements also mean their corners, edges, and front lips should align with the new phones.
Cases with tightly molded camera rings, built-in lens protectors, or unusually precise button covers deserve more caution. Apple doesn't publish the exact height of the camera lenses or coordinates for every button, so the overall dimensions can't rule out tiny changes in those areas.
The iPhone 18 Pro is also heavier despite occupying the same space. Its weight rises from 7.19 ounces to 7.44 ounces, while the Pro Max jumps from 8.22 ounces to 8.78 ounces, reflecting the redesigned internals without affecting case fit.
For practical purposes, the answer is yes. An iPhone 17 Pro case should fit an iPhone 18 Pro, and an iPhone 17 Pro Max case should fit an iPhone 18 Pro Max, although Apple isn't officially guaranteeing the crossover.
