New leaks about the iPhone 18 Pro Max are drawing attention for one reason above all: the battery may grow large enough to challenge the biggest non-foldable iPhone battery ever seen. If the report proves accurate, Apple could be preparing a flagship that changes the battery conversation at the top end of the market.
The most striking part of the rumor is its direct comparison with Samsung’s Galaxy S26 Ultra. The leaked figures suggest the iPhone 18 Pro Max could move beyond the 5,000 mAh level that is expected to define Samsung’s flagship.
Two battery variants are reportedly planned
According to the latest rumor cited by GSM Arena, the iPhone 18 Pro Max will come in two battery versions. The eSIM-only model is said to carry a 5,425 mAh battery, while the version with a physical SIM slot is reportedly set at 5,235 mAh.
This follows the same pattern seen in previous generations, where eSIM-only models gained extra internal space by removing the physical SIM tray. In this leak, that design choice again appears to benefit the eSIM variant.
| iPhone 18 Pro Max Variant | Reported Battery | Key Detail |
|---|---|---|
| eSIM-only | 5,425 mAh | Larger capacity thanks to no physical SIM slot |
| Physical SIM | 5,235 mAh | Still larger than the previous generation |
The jump from iPhone 17 Pro Max would be noticeable
Compared with the iPhone 17 Pro Max, the leak points to a meaningful increase in capacity. The current physical SIM version of the iPhone 17 Pro Max is listed at 4,823 mAh, while the eSIM version is said to sit at 5,088 mAh.
That means the rumored iPhone 18 Pro Max would add 412 mAh on the physical SIM model and 337 mAh on the eSIM version. For Apple, a rise of this size is notable because the company usually focuses more on hardware and software efficiency than on headline battery numbers.
Why the Galaxy S26 Ultra comparison matters
If the 5,425 mAh figure is correct, the iPhone 18 Pro Max would move ahead of the 5,000 mAh battery expected on the Samsung Galaxy S26 Ultra. That would make battery capacity one of the most closely watched battlegrounds in the premium smartphone segment.
Apple and Samsung are often compared for performance, cameras, and displays, but battery size is now part of that rivalry as well. For buyers who care about endurance, the leak gives the iPhone 18 Pro Max a potentially strong advantage on paper.
Still only a rumor for now
Despite the attention the leak is getting, the figures are not official and should still be treated as early information. Apple has not confirmed the battery capacity or any other final specifications for the iPhone 18 Pro Max.
If the rumor turns out to be true, the device could join the top tier of premium phones with one of the largest batteries in the class. For now, the reported 5,425 mAh and 5,235 mAh numbers remain the main talking point around Apple’s next flagship.