Apple has published the iPhone Duo’s battery capacity through its EU energy documentation, which lists a rated capacity of 4,883mAh for the foldable, model A3720, in Apple’s product information sheet. That total matches an earlier leak that split the battery into two cells of 2,962mAh and 1,921mAh. Apple’s label only gives the combined figure, so the individual cell capacities remain unconfirmed by Apple.
The two-cell layout fits Apple’s description of an “iPhone-first dual-battery system.” The phone is also eSIM-only worldwide, which Apple says frees up internal space for battery capacity, so the 4,883mAh figure applies to every market.
| EU label detail | iPhone Duo |
| Rated battery capacity | 4,883mAh |
| Endurance per cycle | 51 hours 30 minutes |
| Endurance in cycles | At least 1,000 |
| Energy efficiency class | A |
| Repairability class | C (2.65/5) |
| User-replaceable battery | No |
| Water and dust protection | IP68 |
Apple’s own battery-life claims depend on which display you use.
| Scenario | Apple’s maximum |
| Typical use | Up to 24 hours |
| Video playback, outer display | Up to 44 hours |
| Video playback, inner display | Up to 31 hours |
| Streamed video, outer display | Up to 37 hours |
| Streamed video, inner display | Up to 26 hours |
Charging is rated for up to 50% in around 20 minutes with a 60W-capable USB-C adapter or higher, or around 30 minutes with a MagSafe charger and a 35W adapter or higher. Wireless charging tops out at 25W.
On paper, the Duo sits between this year’s two larger Pros. The EU sheets rate the iPhone 18 Pro at 4,056mAh and the iPhone 18 Pro Max at 5,391mAh, which makes the Duo about 20.4% larger than the Pro and about 9.4% smaller than the Pro Max.
| Model | Rated capacity | EU endurance per cycle |
| iPhone 18 Pro | 4,056mAh | 52 hours |
| iPhone Duo | 4,883mAh | 51 hours 30 minutes |
| iPhone 18 Pro Max | 5,391mAh | Not listed here |
These are rated capacities, so they aren’t directly comparable with the typical-capacity figures of 4,288mAh and 5,567mAh sometimes quoted for the Pro models. The EU endurance numbers are also close, with the Duo at 51 hours 30 minutes against the Pro’s 52 hours despite its larger battery, which is a reminder that the foldable has two displays to power and capacity alone doesn’t predict real-world battery life.
Apple’s launch timing for the iPhone Duo and its US store setup experience have both been in the news ahead of availability.
M Adnan Akram is the founder and lead writer at Phoonomo, covering mobile technology with a primary focus on Apple and the broader smartphone industry, alongside emerging developments in AI. He follows product launches, spec leaks, and industry trends closely to keep readers informed with timely updates.
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