iPhone 18 Pro Max: Battery leak reveals capacity

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A new leak has revealed the exact battery capacity of the iPhone 18 Pro Max for the first time – and the figures are higher than previously reported. Both the eSIM and the version with a physical SIM slot are said to offer a noticeable increase. However, the source of these figures is far from certain.

The expectation that the iPhone 18 Pro Max will have a larger battery than its predecessor has been a consistent source of speculation for the upcoming Pro generation for months. Concrete figures have been lacking until now – the continuously updated overview of all iPhone 18 Pro rumors has only provided a rough range of around 5,100 to 5,200 mAh. A recent report now presents exact figures that would exceed this estimate – accompanied, of course, by the usual caution when dealing with unverified social media sources.

The leaked battery values in detail

According to the report, the iPhone 18 Pro Max will have two different capacities depending on the SIM card version:

eSIM-only version: 5,425 mAh
Variant with physical SIM slot: 5,235 mAh

For comparison: The iPhone 17 Pro Max has a battery capacity of 5,088 mAh (eSIM) and 4,823 mAh (physical SIM). The increase would therefore be around 337 mAh for the eSIM version and about 412 mAh for the model with a physical SIM slot – a jump that clearly exceeds the previously reported range.

Model variant	iPhone 17 Pro Max	iPhone 18 Pro Max (Leak)	Difference
eSIM-only (including USA)	5,088 mAh	5,425 mAh	+337 mAh (+6.6 %)
With physical SIM (including Germany, Europe)	4,823 mAh	5,235 mAh	+412 mAh (+8.5 %)

It's noteworthy that the version with a physical SIM slot would see a relatively stronger increase in sales. This is a relevant detail for the German market, as devices sold here still have a SIM slot and therefore typically use the smaller SIM card.

Why the eSIM version holds more

The capacity difference between the two versions is not arbitrary, but rather a matter of available space: Eliminating the SIM card slot allows for a slightly larger battery cell. This pattern of two capacities depending on the SIM card type was already evident in the regular iPhone 18 Pro, where the eSIM variant also boasts the larger battery. In the Pro Max, the absolute difference between the two versions would be even more pronounced, at around 190 mAh.

For buyers in Germany, this means that the leaked peak capacity of 5,425 mAh refers to the eSIM-only version, which is not sold in Germany. A more realistic figure would be 5,235 mAh – which, however, would also represent a significant increase compared to the iPhone 17 Pro Max with a physical SIM.

Efficiency as a second lever

Battery capacity alone is only half the story. The iPhone 18 Pro Max is expected to surpass its predecessor not only with a larger battery cell, but also with the more efficient A20 Pro chip, which is rumored to be manufactured using a 2nm process. A more energy-efficient processor can lead to a disproportionate improvement in battery life, even with a moderate increase in capacity. Since the iPhone 17 Pro Max already achieved one of the longest battery life records in its class in independent tests, the upcoming model could extend this figure even further – provided the leaked figures are accurate and the efficiency gains are as expected. Only after actual battery tests on the finished device can this be definitively confirmed.

A leak of unclear origin

As impressive as the figures sound, they should be interpreted with caution. The report relies on scattered social media posts whose original source is difficult to trace. This significantly weakens its validity, because without verifiable origins, it remains unclear whether the data represents actual production figures or merely plausible-sounding estimates.

The strongest argument for its authenticity is the timing: The figures appear simultaneously with the actual data leak at Apple supplier Tata Electronics, whose documents circulating on the dark web so far show all signs of authenticity and are said to contain, among other things, concrete battery specifications for the upcoming Pro models. However, it is not proven whether the capacities now mentioned actually originate from this leak. Until Apple officially unveils the iPhone 18 Pro series in the fall of 2026, the figures remain an interesting but unconfirmed clue – albeit one that fits neatly into the existing picture of an increasing Pro Max battery capacity. (Image: Shutterstock / Jess Rodriguez)