The upcoming iPhone 18 Pro Max will be equipped with a nearly 12% larger battery compared to the iPhone 17 Pro Max, according to an apparent leak.
An alleged photo of a battery pack for a Chinese model of the iPhone 18 Pro Max with a SIM card tray lists a capacity of 5,391 mAh, up from 4,823 mAh for the equivalent iPhone 17 Pro Max battery. The photo was shared on the Korean platform Naver today, but it supposedly originated from the Chinese social media platform Weibo.
The identical 5,391 mAh capacity appeared in a regulatory database last month, so the capacity is looking increasingly likely to be accurate.
For the U.S. model of the iPhone 18 Pro Max, in which the lack of a SIM card tray provides more space for a slightly larger battery, the Naver post claims it will have a 5,567 mAh capacity. The equivalent iPhone 17 Pro Max has a 5,088 mAh battery, so this would work out to be a nearly 10% increase on a year-over-year basis.
Based on this leak, it appears that meaningful battery life gains will not extend to the smaller iPhone 18 Pro. In the U.S., the device will apparently have a 4,288 mAh battery, which would be less than a 1% increase over the iPhone 17 Pro's 4,252 mAh battery in that country. It was previously rumored that the iPhone 18 Pro Max will be thicker than the iPhone 18 Pro, so that might help to explain the difference.
All of the alleged iPhone 18 Pro battery capacities are listed in the table below.
iPhone 18 Pro
| China | China Difference | U.S. | U.S. Difference | |
| iPhone 16 Pro | 3,582mAh | +308mAh | 3,582mAh | +308mAh |
| iPhone 17 Pro | 3,988mAh | +406mAh | 4,252mAh | +670mAh |
| iPhone 18 Pro | 4,056mAh | +68mAh | 4,288mAh | +36mAh |
iPhone 18 Pro Max
| China | China Difference | U.S. | U.S. Difference | |
| iPhone 16 Pro Max | 4,685mAh | +244mAh | 4,685mAh | +244mAh |
| iPhone 17 Pro Max | 4,823mAh | +138mAh | 5,088mAh | +403mAh |
| iPhone 18 Pro Max | 5,391mAh | +568mAh | 5,567mAh | +479mAh |
The capacities differ by region because Apple has continued to include a SIM tray on iPhones sold in some countries outside of the U.S., while U.S. models have been eSIM only since the iPhone 14 lineup. Without a physical tray taking up internal space, Apple can fit a slightly larger battery into the eSIM-only version of each device.
Starting with the iPhone 17 Pro and the iPhone 17 Pro Max, the SIM card tray is also removed on models sold in Canada, Japan, Mexico, Saudi Arabia, the United Arab Emirates, and a few other countries and territories.
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