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Tom’s Guide
Tom’s Guide
Technology
Tom Pritchard

iPhone 18 Pro Max battery leak suggests big changes are coming — what we know

IPhone 17 Pro Max in a London Underground station.

It's been a big week for iPhone 18 Pro leaks, following the unauthorized release of what is reportedly an official drop test of Apple's upcoming flagship. Now we may have just found out exactly how big the iPhone 18 Pro Max's batteries are set to be — and it's good news.

I say batteries because, like last year, Apple is apparently going to release the eSIM-only version of the iPhone 18 Pro Max with a larger battery. According to a now-deleted tweet from X account Fire Universe (via GSMArena), the iPhone 18 Pro Max's eSIM model will come with a 5,425 mAh battery.

Those of you in regions where physical SIM slots are still the norm will apparently have to make do with a smaller 5,235 mAh battery instead.

Assuming this leak is accurate, that would be a huge leap in battery capacity for Apple's largest iPhone. The eSIM iPhone 17 Pro Max had a 5,088 mAh battery, while the model with a physical card slot had 4,823 mAh. This means we could be looking at a 337 mAh increase for the eSIM model and 412 mAh for the physical SIM variant.

For reference, Samsung's Galaxy S26 Ultra has offered the same 5,000 mAh battery as the last several generations of Galaxy flagships. The Pixel 11 Pro XL is also expected to come with an even 5,000 mAh in its battery, which would be a 200 mAh decrease from the 10 Pro XL.

This is a big change for Apple

(Image credit: SonnyDickson)

Historically it was always iPhones that had relatively small batteries, with Android flagships often offering several hundred milliamp hours of extra battery capacity in comparison. So to see the tables turning is quite surprising, even if Apple is still lagging behind brands that have adopted silicon carbon battery technology — like OnePlus.

The fact Apple has opted for smaller batteries hasn't been a major issue over the last few years. There's been a push for energy efficiency and better software optimization, which ensured the largest iPhones had some of the best phone battery life with those smaller batteries.

Needless to say it's going to be interesting to see how well an iPhone 18 Pro Max fares in battery life testing, if it really does come with up to 5,425 mAh of power reserves. We're not likely to see OnePlus 15 levels of battery life, since the 7,300 mAh battery lasted over 25 hours during testing, but we should hopefully still see a marked improvement compared to iPhone 17 Pro Max's 17 hours and 54 minutes.

We'll find out more once the iPhone 18 Pro Max is released later this year, but in the meantime check out our official iPhone 18 Pro Max hub for all the latest news and rumors about the phone.

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