Apple lists the iPhone 18 Pro at 150.0 by 71.9 by 8.75 mm. It lists the iPhone 17 Pro at 150.0 by 71.9 by 8.75 mm. The two are identical to the tenth of a millimetre, and so are the big pair: iPhone 18 Pro Max and iPhone 17 Pro Max are both 163.4 by 78.0 by 8.75 mm.
That settles the size half of the question and leaves the cutout half open. Apple has published no case compatibility statement for either generation, and it is selling a fresh set of iPhone 18 Pro cases rather than telling anyone their old ones carry over.
Key facts
| Item | Detail |
|---|---|
| iPhone 18 Pro dimensions | 150.0 x 71.9 x 8.75 mm, 211 g |
| iPhone 17 Pro dimensions | 150.0 x 71.9 x 8.75 mm, 206 g |
| iPhone 18 Pro Max dimensions | 163.4 x 78.0 x 8.75 mm, 249 g |
| iPhone 17 Pro Max dimensions | 163.4 x 78.0 x 8.75 mm, 233 g |
| Apple case compatibility statement | None published |
| Camera opening measurements | Not published for either generation |
| Design change Apple does describe | The 17 Pro generation shape carries over with a new rear finish |
| Cheapest Apple case for iPhone 18 Pro | Clear Case with MagSafe or Silicone Case with MagSafe, $49 each |
| On sale | Pre-orders Saturday, September 12 at 5 a.m. PT, in stores Friday, September 18 |
The numbers Apple actually publishes
Apple gives exact external dimensions for every iPhone on its tech specs pages, which makes this one of the few case questions that can be answered from primary sources rather than from a vendor’s compatibility chart.
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| Model | Dimensions | Weight | Change versus last year |
|---|---|---|---|
| iPhone 18 Pro | 150.0 x 71.9 x 8.75 mm | 211 g | Same size, 5 g heavier |
| iPhone 17 Pro | 150.0 x 71.9 x 8.75 mm | 206 g | Reference |
| iPhone 18 Pro Max | 163.4 x 78.0 x 8.75 mm | 249 g | Same size, 16 g heavier |
| iPhone 17 Pro Max | 163.4 x 78.0 x 8.75 mm | 233 g | Reference |
Nothing about height, width or thickness moved in either size. The weight did, by 5 g on the small Pro and 16 g on the Pro Max, which affects how a wrist strap or a crossbody strap feels and does not affect whether a shell closes around the phone.
What did change on the back
Apple describes the iPhone 18 Pro as carrying the 17 Pro generation design forward with a new rear finish, on an aluminium unibody with Ceramic Shield 2 on the front and Ceramic Shield on the back. The body is not the variable.
The camera is. The 48MP Fusion main camera now has a variable aperture running f/1.48, f/1.8, f/2.8 and f/4.0 through six laser-cut blades, which is new mechanical hardware sitting behind the main lens. The three focal lengths themselves are unchanged from the 17 Pro: a 24 mm main, a 13 mm ultra wide and a 100 mm 4x telephoto.
Apple does not publish the dimensions of the camera plateau, the diameter of the lens openings or the position of the buttons in millimetres, for the 17 Pro or the 18 Pro. So the one measurement that decides whether an old case works is the one measurement that has never been on a spec page. The generation-to-generation differences are documented everywhere except in the place a case buyer needs them.
The cases Apple is selling instead
Apple lists six first-party accessories against the iPhone 18 Pro in the US, and describes none of them as compatible with an earlier phone.
- TechWoven Case with MagSafe, $59
- Clear Case with MagSafe, $49
- Silicone Case with MagSafe, $49
- FineWoven Wallet, $59
- Wrist Strap, $29
- Crossbody Strap, $59
Prices differ by country: Apple lists the TechWoven case at C$79 in Canada, A$99 in Australia, 69 euros in Germany and S$89 in Singapore, alongside a $1,199 starting price for the phone itself. A wallet, a wrist strap and a crossbody strap attach magnetically rather than wrapping the body, so they are the accessories least affected by any of this.
What has not been confirmed
Apple has not published a case compatibility list, a statement that iPhone 17 Pro cases fit the iPhone 18 Pro, or a statement that they do not. It has not published camera opening sizes, button positions in millimetres, or the layout of the MagSafe magnet array for either generation. It has not said whether the new rear finish changes anything a case touches.
What can be said from Apple’s own figures is narrow and real: the outside dimensions are the same, so an iPhone 17 Pro case will physically go onto an iPhone 18 Pro of the matching size. Whether the openings line up is a question Apple has left to the moment you try it, and the camera opening is the part to look at first.
Pre-orders open at 5 a.m. PT on Saturday, September 12, and the phones reach stores on Friday, September 18. That Friday is the first day anyone can test an old case on a new phone, which is also the first day a genuine answer will exist.
