Apple has published the overall battery capacity of the two-battery iPhone Duo in a regulatory filing, showing exactly how it compares to the iPhone 18 Pro and other recent models. The figure is 4883 mAh, according to Apple's EU Energy Labels submission.
Initial rumors suggested the iPhone Duo would have the largest battery capacity of any iPhone ever made. Real-world tests later showed it performs practically the same as the iPhone 18 Pro, and the official numbers now clarify where it sits. The iPhone Duo beats the iPhone 18 Pro but falls short of the iPhone 18 Pro Max, which has 5391 mAh.
In decreasing order of battery capacity, Apple's most recent iPhones are: iPhone 18 Pro Max at 5391 mAh, iPhone Duo at 4883 mAh, iPhone 17 Pro Max at 4823 mAh, iPhone 18 Pro at 4056 mAh, iPhone 17e and iPhone 16e at 4005 mAh each, iPhone 17 Pro at 3988 mAh, iPhone 17 at 3692 mAh, and iPhone Air at 3149 mAh.
Apple's filing does not show how the total is divided between the two batteries. However, the 4883 mAh figure matches rumors from July 2026, which said the batteries would be 1921 mAh and 2962 mAh. Early Geekbench results show the iPhone Duo and iPhone 18 Pro performing similarly, scoring 3986 and 3390 in single-core tests, and 11,067 and 11,540 in multi-core tests. Both sets of results fall within the margin of error, suggesting the two devices should perform indistinguishably in everyday use.
Source: AppleInsider · Summarized by HeadlinesBriefing