You're standing in the aisle, or maybe you're scrolling through a sketchy eBay listing, and you see it. A gorgeous leather case for an iPhone 15 Pro Max. It’s on sale. It looks huge. Your iPhone 15 Plus is also huge. They both have that 6.7-inch screen, right? It seems like a no-brainer.
It isn't.
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Honestly, the short answer is no. If you try to force it, you're going to end up with a phone that feels like it's wearing someone else's shoes. Will a 15 Pro Max case fit a 15 Plus? Technically, you can physically shove the phone inside most of them, but you’ll probably regret it within five minutes of trying to take a photo or change the volume.
Let's get into the weeds of why this happens.
The Illusion of the 6.7-Inch Screen
Apple is great at marketing "one size" for two different phones. Both the iPhone 15 Plus and the iPhone 15 Pro Max are marketed as having 6.7-inch displays. Naturally, you’d assume the chassis—the actual body of the phone—is identical.
They aren't.
The iPhone 15 Plus is actually a bit taller and wider than the Pro Max. If you look at the raw numbers, the Plus sits at about 160.9mm tall and 77.8mm wide. Meanwhile, the Pro Max, thanks to those thinner bezels Apple loves to brag about, is slightly more compact at 159.9mm by 76.7mm.
Think about that.
A whole millimeter difference in width might not sound like much when you're looking at a ruler, but in the world of precision-molded TPU and polycarbonate, it’s a canyon. A Pro Max case is designed to be tight. If you try to squeeze the wider 15 Plus into it, the sides of the case will bow out. You’ll lose that "lip" that protects your screen when you drop it face-down.
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Why thickness matters more than you think
It gets weirder with the depth. The iPhone 15 Plus is actually thinner (7.8mm) than the Pro Max (8.25mm).
So, here is the situation:
- Your Plus is too wide for the case.
- Your Plus is too tall for the case.
- But it’s too "skinny" for the case's depth.
The result is a phone that feels like it’s bursting at the seams horizontally but rattling around vertically. It’s an ergonomic nightmare.
The Camera Bump Catastrophe
This is where the plan really falls apart. The iPhone 15 Pro Max has a massive triple-lens array with that 5x tetraprism zoom. The iPhone 15 Plus has a much simpler dual-lens setup.
When you put a 15 Plus into a Pro Max case, you're going to have a giant, awkward gap in the camera cutout. Dust, lint, and sand will find their way into that gap immediately. Within a week, the back of your $900 phone will be covered in micro-scratches from the debris trapped between the glass and the case.
More importantly, the Pro Max's camera bump is significantly thicker. Cases for the Pro Max have a high protective ridge around the camera. Because the Plus has a flatter camera module, it won't sit flush against that ridge. You’re essentially leaving your lenses unprotected while simultaneously making the phone harder to pull out of your pocket.
Buttons and Switches: The Action Button Problem
This is the dealbreaker for most people. The iPhone 15 Pro Max features the Action Button. This is a physical, clickable button that replaced the old-school mute switch.
The iPhone 15 Plus? It still has the classic Mute Switch.
Most iPhone 15 Pro Max cases are designed with a solid button cover for the Action Button. If you put your 15 Plus in there, that solid button cover will be sitting right on top of your Mute Switch. You won't be able to toggle it. You’ll have to take the case off just to silence your phone for a meeting or a movie.
Even if you find a Pro Max case that has a cutout (which is rare for the Pro models), the alignment is off. Apple shifted the internal components just enough that the volume rockers won't line up perfectly either. You’ll find yourself pressing the "Up" button and getting no response, or worse, having the case permanently hold the "Down" button, sending your phone into a volume-plunge or triggering a random SOS call.
The USB-C Port Alignment
Both phones finally moved to USB-C in 2023, which was a win for everyone. However, the cutouts on the bottom of the cases are specific to the thickness of the frame.
Because the Pro Max is thicker and made of titanium, the port is centered differently than on the aluminum frame of the 15 Plus. I've seen people try this swap only to realize their favorite charging cable won't plug in all the way because the case is blocking the "neck" of the USB-C connector.
What Actually Fits the iPhone 15 Plus?
If you’re looking for a cheaper case or a specific design, don't look at the Pro Max.
Surprisingly, the iPhone 14 Plus cases are a much closer match. They aren't perfect—the mute switch is slightly moved and the camera bump on the 15 Plus is a tiny bit bigger—but they are way more compatible than a Pro Max case will ever be.
If you want a perfect fit, you really have to buy a case specifically labeled for the iPhone 15 Plus. Brands like Spigen, OtterBox, and even the cheap Amazon alternatives have finally caught up with the "Plus" sizing. It used to be the "forgotten" middle child of the lineup, but since the 14 Plus, the market is flooded with dedicated options.
Actionable Next Steps
If you currently have a 15 Pro Max case in your hand and you're wondering if you should keep it for your Plus, here is the move:
- Check the return policy. If it’s unopened, send it back. It is not worth the frustration of misaligned buttons.
- Inspect the "Lip." If you absolutely must use it in an emergency, check if the screen's edges are actually covered. If the case is bowing out because the Plus is too wide, it won't protect your screen during a drop.
- Test the Mute Switch. If you can't reach the toggle without using a toothpick, ditch the case.
- Look for "Plus" Specifics. When shopping, double-check that the packaging says "iPhone 15 Plus" specifically, not "6.7-inch iPhone." Manufacturers sometimes use vague labeling that leads to this exact confusion.
Stick to cases made for your specific model. Your 15 Plus is a premium device; don't compromise its safety and your sanity just to save a few bucks on a Pro Max clearance item.