The iPhone 18 Pro Max is shaping up to deliver the largest battery Apple has ever put in an iPhone, according to a report from Macworld citing supply chain sources. The Pro Max models will ship with 5,425 mAh capacity when equipped with eSIM and 5,235 mAh with a physical SIM card, representing a 6.6% and 8.5% jump respectively over the iPhone 17 Pro Max’s 5,088 mAh and 4,823 mAh. The figures exceed previous estimates that had pegged the iPhone 18 Pro Max battery at 5,100 to 5,200 mAh, marking a more aggressive battery upgrade than initially expected.
Macworld points to social media posts that are difficult to trace to their original source, though the timing coincides with a recent confirmed data breach at Apple supplier Tata Electronics. Whether these specific battery numbers originated from that breach remains unclear, but earlier supply chain information from leaker Digital Chat Station had already signaled a meaningful battery increase coming to the Pro Max line. The consistency between multiple sources lends the figures some credibility, even if the pathway from manufacturing data to public disclosure remains opaque.
The iPhone 18 Pro will use the A20 chip built on TSMC’s 2nm process, which is expected to be 15% faster and 30% more efficient than the A19. Combined with the larger physical battery, that efficiency gain should allow Apple to deliver battery life improvements beyond the iPhone 17 Pro Max‘s current 39-hour rating. Apple will also swap Qualcomm’s 5G modem for an in-house C2 modem, another efficiency win that compounds over a full day of use.
The standard iPhone 18 Pro battery capacity is expected to grow to 3,582 mAh (eSIM) and 3,412 mAh (physical SIM), up from the iPhone 17 Pro’s 3,274 mAh and 3,104 mAh. That is a 9.4% and 10% increase respectively, suggesting Apple is investing in battery capacity across the entire flagship lineup, not just the Max variant.
The iPhone 17 Pro Max already holds the distinction of being the longest-lasting phone tested among 34 competitors in independent lab testing, so the bar is high. Most competing flagship phones still rely on Qualcomm modems, which consume more power than Apple’s custom silicon; the C2 modem is Apple’s most direct lever for closing that gap on efficiency alone.
The iPhone 18 Pro and Pro Max are expected to launch in September 2026, alongside a foldable “iPhone Ultra.” More affordable iPhone 18 and iPhone 18e models will follow in spring 2027. Analysts expect the iPhone 18 Pro to start at $1,399, suggesting meaningful price increases for the flagship line.
