iPhone 18 Pro Max tipped to be 'heaviest iPhone ever' — here’s 3 reasons why that’s a good thing

Usually, I love it when phones get thinner and lighter, but that may not be the case with the iPhone 18 Pro Max if rumors are true about it getting thicker and heavier. Ice Universe reports that the upcoming flagship model will measure around 9mm thick and weigh approximately 7 grams more than the current iPhone 17 Pro Max (that's a 0.25mm increase in thickness).

Apparently, the added heft can be largely attributed to the larger batteries that the company is planning to use. Regulatory filings show a 5,567 mAh battery bound for the U.S. and a 5,391 mAh battery for China—representing a massive 500 mAh increase in capacity. Given that jump, it makes complete sense why the iPhone 18 Pro Max’s weight is ballooning.

I totally understand this move, as battery life continues to be a top priority for any smartphone user, but it does expose a dilemma that Apple continually faces in its attempt to balance design and endurance. There’s good and bad to this latest iPhone 18 Pro Max rumor, so let me break down the pros and cons.

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iPhone 18 Pro Max: Rumored size comparison

Longer battery life

I’ve tested the last few iPhone generations and, for the most part, each subsequent model offers improved battery life. While the rumors hint that the iPhone 18 Pro Max will get a significant capacity boost, that extra juice consequently means a thicker and heavier design.

More capacity will simply allow the upcoming flagship to last much longer on a single charge. Based on the rumors, the battery will be 9.87% larger than the one in the iPhone 17 Pro Max — though it’s difficult to say if that will translate to an identical percentage jump in real-world endurance. Of course, a lot of it also boils down to the power efficiency of the upcoming A20 Pro chip.

Despite that, I fully expect the iPhone 18 Pro Max to eclipse the 18-hour and 42-minute average that the iPhone 17 Pro Max achieved in our battery drain test. However, it'll still take a lot more than a 10% battery bump to dethrone the true endurance warriors on our best phone battery life list — like the OnePlus 15, which reached a mind-boggling time of 25 hours and 13 minutes.

Materials do matter

Just the other day, while I was lying on my back and holding my iPhone 17 Pro, I lost my grip. In slow-motion fashion, I reacted quickly enough to move my face out of the way and prevent a head-on collision. What I momentarily forgot — and abruptly rediscovered at that second — was just how dense this thing is. I think many of us don’t regularly consider the amount of force these glass-and-metal slabs can apply on impact.

That’s why I would usually prioritize a smaller, lighter design, knowing full well it comes at the expense of battery life. Rumors suggest the iPhone 18 Pro Max will feature a new vapor chamber design made of stainless steel, which is another potential contributing factor to its increased size and weight.

The iPhone 14 Pro Max currently stands as the heaviest iPhone ever, but the 18 Pro Max is tipped to match or even beat its 240-gram weight. It's a fascinating cycle to look back on. Apple famously ditched the heavy stainless steel of the 14 Pro Max in favor of a lighter titanium frame on the 15 Pro Max, bringing the weight down significantly. While Apple moved to a less-dense aluminum alloy for the 17 Pro Max, internal design changes and a physically larger footprint pushed the weight back up anyway.

My point here is that materials matter. While the internal vapor chamber is rumored to be constructed out of heavier stainless steel, I’m hoping Apple sticks to lightweight aluminum for the rest of the chassis.

I also think it’s worth pointing out Apple's ongoing reluctance to adopt silicon-carbon batteries. This newer battery tech can stow more charge without increasing a battery’s overall physical footprint, keeping devices incredibly slim while delivering stellar endurance. It's already proving to be a game-changer for competitors, and it's a shame Apple hasn't made the leap.

Performance gains

Finally, I think it’s worth calling out the new vapor chamber design. Power users know the benefits of having one, mainly because of how it boosts sustained performance. I’m confident that the upcoming A20 Pro chip — which is expected to move to an ultra-efficient 2nm manufacturing process — will inherently improve upon the current A19 Pro, but a robust cooling system ensures it can actually maintain that peak performance for much longer.

Heat kills a processor’s performance, and along with it, battery health. Even though the iPhone 18 Pro Max may get thicker and heavier partly due to this new vapor chamber design, I think the compromise will be well worth it in the long run. Processor-intensive tasks — like playing graphically taxing games or editing 4K video footage on the fly — will be handled much better without the phone aggressively throttling.

Regardless, I’m not entirely surprised by the revelation that the 18 Pro Max could be a heavyweight. What I’m really curious about now is the price. So far, iPhones have largely been spared from major price hikes, but we could very well see a change when this flagship drops later this fall.

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