A leaked photo appearing to show the iPhone 18 Pro Max battery suggests Apple’s next flagship could pack a 5,391 mAh cell — roughly 12% more than the iPhone 17 Pro Max’s 4,823 mAh. If accurate, this would represent the largest battery ever placed in an iPhone and a meaningful jump in real-world endurance. The standard iPhone 18 Pro, however, reportedly gains less than 1% over its predecessor, making the gap between the two Pro models wider than ever.
What you need to know
- The leaked iPhone 18 Pro Max battery capacity is 5,391 mAh (SIM-tray version) or 5,567 mAh (eSIM-only version), up from 4,823 mAh and 5,088 mAh respectively on the iPhone 17 Pro Max.
- The same 5,391 mAh figure reportedly appeared in a regulatory database a month before the photo surfaced, lending it additional credibility.
- The iPhone 18 Pro’s battery is said to be 4,288 mAh (eSIM) — barely up from the iPhone 17 Pro’s 4,252 mAh, a sub-1% increase.
- All figures remain unconfirmed leaks; Apple has not officially announced the iPhone 18 lineup.
Larger batteries expected in the new iPhones
How big is the Pro Max battery increase?
The leaked photo, which first appeared on the Korean platform Naver and apparently originated on the Chinese social network Weibo, shows a battery labeled for the Chinese-market iPhone 18 Pro Max — a variant that retains a physical SIM-card tray. The stated capacity of 5,391 mAh represents an approximately 12% increase over the iPhone 17 Pro Max’s 4,823 mAh cell in the equivalent SIM-tray configuration.
According to the source, the same 5,391 mAh figure had already surfaced in a regulatory database roughly a month earlier. When two independent sources converge on the same number, the leak carries more weight — though it remains unconfirmed until Apple makes an official announcement.
Alleged iPhone 18 Pro Max battery
The source estimates that a roughly 10% capacity bump could translate into an extra hour to hour-and-a-half of screen-on time in demanding scenarios such as navigation or video recording. That is a rough projection, not a tested result, and actual gains will depend on software optimization, display efficiency, and the new A20 Pro chip’s power characteristics.
Why SIM-tray and eSIM models have different capacities
One detail that often surprises buyers: the same iPhone model can ship with different battery sizes depending on the market. The reason is straightforward — the physical SIM-card tray takes up internal space. In the United States, Apple dropped the SIM slot entirely starting with the iPhone 14, switching to eSIM only. That freed up room for a slightly larger battery.
For the eSIM-only iPhone 18 Pro Max, the leaked capacity is 5,567 mAh, compared to 5,088 mAh for the iPhone 17 Pro Max — a gain of roughly 10% year over year.
Starting with the iPhone 17 Pro and iPhone 17 Pro Max, Apple extended the eSIM-only approach to additional markets including Canada, Japan, Mexico, Saudi Arabia, and the UAE. In markets that still receive a SIM-tray model, the battery is correspondingly smaller.
The larger iPhone shows a substantial capacity increase
Here are all the leaked and known figures compiled from the source:
| Model | SIM-tray version | eSIM-only version |
|---|---|---|
| iPhone 16 Pro | 3,582 mAh | 3,582 mAh |
| iPhone 17 Pro | 3,988 mAh | 4,252 mAh |
| iPhone 18 Pro | 4,056 mAh | 4,288 mAh |
| iPhone 16 Pro Max | 4,685 mAh | 4,685 mAh |
| iPhone 17 Pro Max | 4,823 mAh | 5,088 mAh |
| iPhone 18 Pro Max | 5,391 mAh | 5,567 mAh |
The standard iPhone 18 Pro barely gains any capacity
While the Pro Max sees a significant jump, the regular iPhone 18 Pro reportedly receives a far more modest upgrade. According to the same leak, the eSIM-only version will carry a 4,288 mAh battery, up from 4,252 mAh in the iPhone 17 Pro — a gain of less than 1%. In practical terms, that difference is negligible and unlikely to produce any noticeable change in daily battery life.
The source attributes this disparity to the iPhone 18 Pro Max reportedly being noticeably thicker than the standard Pro model. A thicker chassis simply provides more physical volume for a larger battery cell, and Apple appears to have directed most of the capacity gains toward the larger device.
What this means — and what remains uncertain
Would you buy the new flagship for its battery life?
If these leaked figures hold, the iPhone 18 Pro Max would set a new record for iPhone battery capacity, and the ~12% year-over-year increase for the SIM-tray model is a substantial improvement by Apple’s historically conservative standards. For buyers choosing between the two Pro models, battery life becomes an even stronger argument in favor of the Max.
That said, these are still leaks, not confirmed specifications. The convergence of the forum photo and the earlier regulatory filing is encouraging, but final numbers could still shift before Apple’s official announcement. Battery capacity alone also does not determine real-world endurance — processor efficiency, display technology, and software optimization all play critical roles. Until independent testing of production units is available, any projections about hours of use remain estimates.
