Apple has shared the battery size of its first foldable phone. The iPhone Duo has a 4,883 mAh battery, according to an EU energy label published on October 16. The phone goes on sale on October 23, 2026. The label also confirms that the battery is made of two cells.
The two cells hold 2,962 mAh and 1,921 mAh. Add them together, and you get the full 4,883 mAh. In short, the battery is split in two, with one larger cell and one smaller cell. Reports had hinted at a two-cell design before, and this label backs that up.
The iPhone Duo works only with eSIM. There is no SIM tray in the phone. That frees up room inside, which Apple can use for other parts.
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The Duo sits between two of Apple's newest phones. iFixit has reported that the eSIM-only iPhone 18 Pro has a 4,288mAh battery. The iPhone 18 Pro Max has a bigger one at 5,567 mAh. So the Duo beats the Pro by 595mAh but trails the Pro Max by 684mAh.
Still, size is not the whole story. Screen size, software, the chip, and how you use the phone all affect battery life. A foldable adds one more question. You can use the small outer screen or the large inner one.
The big screen will likely use more power. Someone who watches videos on the big screen may drain the battery faster than someone who mostly texts on the small one. How often you keep the phone open will matter.
The EU label confirms the numbers on paper. Real battery life is still unknown. Independent tests and daily use will show how long the iPhone Duo lasts. For buyers who want a bigger screen and good battery life, those results will matter.