The iPhone Duo has a 4,883 mAh battery split into two cells and a rated endurance of 51 hours and 30 minutes per charge, according to the EU energy label Apple published on Friday. The battery is rated to hold up for 1,000 charge cycles. If you’re thinking about Apple’s first foldable, which starts at $1,999 and reaches stores on October 23, this is the first official look at how long it will last.
What did Apple’s energy label reveal?
Apple posted the document on October 16, the same day pre-orders opened. Until then, the battery size existed only as a leak. A July leak showed two cells, one at 2,962 mAh and one at 1,921 mAh. Those add up to exactly 4,883 mAh, and MacRumors says the label appears to confirm it.
The iPhone Duo is eSIM-only, so there’s no version with a physical SIM tray taking up room inside. That’s why GSMArena and MacRumors both expect the same capacity in the US and everywhere else.
The label also gives two other numbers. Rated endurance is 51 hours and 30 minutes per cycle, which is a lab-style figure measured by a set method, not a promise of how long it lasts in your pocket. And the battery is rated to keep at least 80% of its original capacity after 1,000 charge cycles under default settings. A cycle is one full charge’s worth of power, even if you get there through several small top-ups.
How does it compare to other phones?
MacRumors cites an iFixit teardown for two other iPhones: the iPhone 18 Pro at 4,288 mAh and the iPhone 18 Pro Max at 5,567 mAh. The Duo sits in between, with about 600 mAh more than the Pro and about 700 mAh less than the Pro Max.
Among foldables, Brazilian site Canaltech made the most direct comparison, against Samsung’s Galaxy Z Fold 8:
| iPhone Duo | Galaxy Z Fold 8 | |
|---|---|---|
| Capacity | 4,883 mAh | 4,660 mAh |
| Rated endurance per charge | 51h30 | 49h10 |
| Rated charge cycles | 1,000 | 1,200 |
The Duo wins on capacity and endurance per charge. The Fold 8 wins on battery lifespan. Canaltech’s own back-of-the-envelope math puts the Duo at roughly 51,500 total hours across its rated cycles and the Fold 8 above 58,800. That’s the site’s estimate, not an official figure, but it shows the scale of the gap.
Some Chinese foldables carry bigger batteries, including the Xiaomi 18 Fold at 6,000 mAh and the Huawei Pura X Max at 5,300 mAh. Capacity alone doesn’t settle it, though. Chip efficiency, screen power draw and software all change real-world results, which is why the hours-per-cycle rating is more useful than milliamp-hours by themselves.
Does it change whether you should buy?
In practice, 51 hours per cycle suggests you should get past a day and a half of moderate use between charges, which is welcome on a phone with a 7.6-inch inner display and a 5.4-inch outer one. Lab numbers usually run ahead of real use, so plan on less, but comparing two phones measured the same way still holds.
On the 1,000-cycle rating: if you charge once a day, you hit it in about two years and nine months, and the battery would still be at 80%. The Fold 8’s 1,200 cycles stretch that by roughly six months. If you upgrade before then, the gap never shows up. If you plan to keep the phone five years, factor in a battery replacement and check what Apple charges for it before you buy.
Price and availability
Pre-orders opened October 16 and deliveries start October 23. In the US the iPhone Duo starts at $1,999 for 256GB, as we covered in our iPhone Duo pre-order breakdown. At that price, battery is only one factor. If it’s your top priority, compare the Duo against Apple’s Pro models, brush up with our guide on making your phone battery last longer, and wait for independent tests, since an energy label measures under controlled conditions.
