Apple has confirmed the iPhone Duo’s battery capacity at 4,883 mAh, revealing how much power the company’s first foldable iPhone packs ahead of its October 23 retail release.
The figure appears in an EU energy label published on Apple’s regulatory website, confirming an earlier leak that identified two battery cells inside the device. One has a capacity of 2,962 mAh, while the other holds 1,921 mAh.
Unlike some other iPhone models, the Duo is available only with eSIM, so every unit sold worldwide has the same 4,883 mAh capacity.
How the iPhone Duo Compares to the iPhone 18 Pro
The Duo sits between Apple’s two flagship Pro models in battery capacity, offering more than the smaller iPhone 18 Pro but falling short of the Pro Max.
- iPhone 18 Pro: 4,288 mAh
- iPhone Duo: 4,883 mAh
- iPhone 18 Pro Max: 5,567 mAh
That gives the Duo 595 mAh more capacity than the smaller Pro, but 684 mAh less than the Pro Max.
Interestingly, the gap is much smaller than last year’s iPhone 17 Pro Max, which has a 5,088 mAh battery. That’s just 205 mAh more than the Duo.
Battery capacity doesn’t tell the whole story, however. Apple claims the Duo can deliver five additional hours of screen-on time compared with the iPhone 17 Pro Max when primarily using its outer display.
That suggests the A20 Pro chip and Apple’s power management could offset the smaller battery, though real-world testing will be needed to see how the Duo performs when it uses its larger inner screen extensively.
Why Apple Uses Two Batteries
The Duo’s folding design leaves less room for a conventional battery arrangement.
Instead, Apple splits the capacity between two cells in opposite halves of the device, letting the phone stay slim while fitting a 5.4-inch outer display and a 7.6-inch folding screen.
The larger display will naturally place different demands on battery life, making actual endurance more important than capacity alone.
The iPhone Duo reaches stores on October 23, but pre-order delivery estimates have already slipped into 2027 because of limited launch inventory. Apple Store walk-in availability is also expected to be extremely limited.
