The iPhone 18 Pro Max could get a major battery upgrade this year. A new leak claims Apple’s largest 2026 iPhone could pack a 5,567mAh battery in the U.S., which would be nearly 10% larger than the iPhone 17 Pro Max battery.
The reported upgrade is especially notable because the smaller iPhone 18 Pro may see almost no increase in battery capacity. If the figures are accurate, Apple could be creating a much bigger battery gap between its two Pro models.
iPhone 18 Pro Max Could Get a 12% Larger Battery
An alleged photo of an iPhone 18 Pro Max battery for the Chinese market shows a capacity of 5,391mAh. The image was shared on Naver, although it reportedly originated from Weibo.
That figure is significant because the same 5,391mAh capacity appeared in a regulatory database last month. A second appearance doesn’t confirm the specification, but it makes the number more credible than a single unverified leak.
The U.S. version could reportedly have an even larger battery. According to the latest leak, the U.S. iPhone 18 Pro Max will have a 5,567mAh battery, compared with 5,088mAh for the U.S. iPhone 17 Pro Max.
That’s an increase of 479mAh, or about 9.4% year over year.
The reason for the difference between the Chinese and U.S. models is reportedly the physical SIM tray. iPhones sold in the U.S. have been eSIM-only since the iPhone 14 lineup, allowing Apple to use the space that would otherwise be occupied by a SIM card tray.
Apple has expanded its eSIM-only approach to additional markets with the iPhone 17 Pro and iPhone 17 Pro Max, so battery capacities can vary depending on the region.
iPhone 18 Pro May Get Almost No Battery Upgrade
The most interesting part of the leak may be the difference between the iPhone 18 Pro and iPhone 18 Pro Max.
The U.S. iPhone 18 Pro is reportedly set to have a 4,288mAh battery. That’s just 36mAh more than the 4,252mAh battery attributed to the U.S. iPhone 17 Pro, representing an increase of less than 1%.
The Chinese iPhone 18 Pro could reportedly move from 3,988mAh to 4,056mAh, a somewhat larger increase but still modest compared with the Pro Max.
| Model | China | U.S. |
|---|---|---|
| iPhone 16 Pro | 3,582mAh | 3,582mAh |
| iPhone 17 Pro | 3,988mAh | 4,252mAh |
| iPhone 18 Pro | 4,056mAh | 4,288mAh |
| iPhone 16 Pro Max | 4,685mAh | 4,685mAh |
| iPhone 17 Pro Max | 4,823mAh | 5,088mAh |
| iPhone 18 Pro Max | 5,391mAh | 5,567mAh |
The reported difference could be partly explained by Apple’s rumored changes to the physical design. The iPhone 18 Pro Max has previously been tipped to be thicker than the iPhone 18 Pro, potentially giving Apple more internal space for a larger battery.
Of course, battery capacity doesn’t directly translate to battery life. Apple’s A-series chip, display, modem and software optimizations all play a role in how long an iPhone lasts on a charge.
Even so, a battery approaching 5,600mAh would represent a substantial increase for Apple’s largest iPhone.
For the iPhone 18 Pro Max, the reported 5,567mAh capacity would be 479mAh more than the iPhone 17 Pro Max, while the smaller iPhone 18 Pro could gain just 36mAh in the U.S.
The figures remain unconfirmed until Apple announces the iPhone 18 lineup. But with the 5,391mAh capacity reportedly appearing in both a leak and a regulatory database, the possibility of a significant iPhone 18 Pro Max battery upgrade is becoming increasingly interesting.
