Apple’s iPhone 18 Pro Max might finally get the battery upgrade fans have been asking for. A fresh leak claims the phone’s battery capacity is growing by nearly 12% over last year’s model, based on an alleged photo of the battery pack itself.
The image reportedly shows a battery built for the Chinese version of the iPhone 18 Pro Max, listing a capacity of 5,391 mAh. That is a solid jump from the iPhone 17 Pro Max’s 4,823 mAh battery in the same region.
Here’s what we know so far, and why this leak looks more credible than most.
A Leaked Photo Points to 5,391 mAh
According to recent reports, a photo of an iPhone 18 Pro Max battery pack surfaced on the Korean blogging platform Naver. The post claims the image originally came from Weibo, a Chinese social media site that’s been a source for Apple leaks before.
The battery in the photo includes a SIM card tray, which means it’s built for markets like China that still use physical SIM cards. It lists a capacity of 5,391 mAh.
This isn’t a totally new number either. The same 5,391 mAh figure reportedly showed up in a regulatory database last month, which adds real weight to this leak. When two separate sources point to the same number, it’s usually a good sign the spec is close to final.
U.S. Model Gets an Even Bigger Bump, But the Pro Misses Out
For the U.S. version of the iPhone 18 Pro Max, which skips the SIM tray in favor of an eSIM-only design, the leak claims a slightly bigger 5,567 mAh battery. Since there’s no physical tray taking up space, Apple can squeeze in extra battery capacity. Compared to the iPhone 17 Pro Max’s 5,088 mAh U.S. battery, that’s close to a 10% increase.
The smaller iPhone 18 Pro doesn’t seem to be getting the same treatment. Leaks suggest its U.S. battery will only grow from 4,252 mAh to 4,288 mAh, less than a 1% bump. That barely counts as an upgrade.
Read Also: iPhone 18 Pro Max Leaks: Specs, Camera & Price Rumors
One possible reason: the iPhone 18 Pro Max is rumored to be slightly thicker than the standard Pro model this year, which would leave more internal room for a larger cell.
Leaked Battery Capacities at a Glance
| Model | China | U.S. |
| iPhone 17 Pro | 3,988 mAh | 4,252 mAh |
| iPhone 18 Pro (leaked) | 4,056 mAh | 4,288 mAh |
| iPhone 17 Pro Max | 4,823 mAh | 5,088 mAh |
| iPhone 18 Pro Max (leaked) | 5,391 mAh | 5,567 mAh |
What a Bigger Battery Actually Means for You
Battery life has been one of the most common complaints about Apple’s Pro Max lineup, especially from users who game, record video, or run Apple Intelligence features all day. A near double-digit percentage increase in battery capacity could translate into real, noticeable gains in screen-on time, not just marketing numbers.
It also lines up with a pattern Apple has followed for years, where the Pro Max gets better battery life than the smaller Pro, partly because of its bigger frame.
Availability
The iPhone 18 Pro and iPhone 18 Pro Max are expected to launch in September 2026, alongside the rest of Apple’s fall lineup. Since this is still based on leaked and regulatory information, Apple has not confirmed any battery specifications yet.
Should You Believe This Leak?
Two independent leaks now pointing to the same 5,391 mAh figure makes this one of the more believable battery rumors we’ve seen for the iPhone 18 series. If accurate, the iPhone 18 Pro Max could be Apple’s biggest battery life upgrade in years, while the standard Pro model gets left with only a minor bump.
As always, nothing is official until Apple confirms it at launch. We’ll keep tracking this one closely.
