iPhone Duo Battery Life Results Are In — Here's How It Compares to Other Foldables (and iPhone 18 Pro Max)

The introduction of the iPhone Duo marks a massive milestone in Apple's hardware lineup, bringing the company into the foldables market. However, stepping into foldable territory invariably involves compromises—ranging from a dual-camera setup and a shorter cover screen to a physical battery capacity noticeably smaller than what you'll find in the flagship iPhone 18 Pro Max. But when evaluating smartphone longevity, physical size only tells part of the story; real-world and standardized benchmark testing are essential to determine true daily endurance.

iPhone Duo Battery Life Results

Tom's Guide put the iPhone Duo through a rigorous, custom battery life test designed to accurately simulate ordinary daily usage. The benchmark involves continuous web surfing over a 5G connection with screen brightness set to a consistent 150 nits. For foldable devices, this demanding test is deliberately executed using the larger, primary folding screen.

When tested side-by-side with industry competitors, the iPhone Duo achieved a respectable battery life result of 13 hours and 20 minutes using its 4,883 mAh battery. Unsurprisingly, the non-folding iPhone 18 Pro Max outpaced it significantly, lasting 17 hours and 31 minutes, fueled by its larger 5,567 mAh capacity and traditional single-screen power efficiency.

How does the iPhone Duo stack up against major Android foldables? When compared directly against the Samsung Galaxy Z Fold 8 (which packs a very similar 4,800 mAh battery), the iPhone Duo lasted over three hours longer. While older reviews for the Z Fold 8 clocked it at 12 hours and 19 minutes under slightly different lab conditions, a direct simultaneous retest showed the Z Fold 8 yielding 10 hours and 6 minutes—highlighting Apple's superior processor energy efficiency and optimized power consumption on iOS. Meanwhile, the Samsung Galaxy Z Fold 8 Ultra managed 14 hours and 33 minutes thanks to a slightly larger 5,000 mAh cell.

Google's Pixel 11 Pro Fold (4,806 mAh battery) fell behind the iPhone Duo by nearly 50 minutes, tapping out at 12 hours and 31 minutes. At the top end of the capacity spectrum, the Motorola Razr Fold, boasting a massive 6,000 mAh battery, led the foldable category with an impressive 14 hours and 44 minutes of continuous runtime.

iPhone Duo Charging Speed and Rejuvenation

Beyond raw longevity, how quickly a device can refuel is vital for modern users. The iPhone Duo supports up to 60W wired charging, mirroring the specifications of the iPhone 18 Pro Max. However, charging rates are not identical in practice.

During testing, the iPhone Duo reached 42% charge in 15 minutes and 66% in 30 minutes. In comparison, the iPhone 18 Pro Max pulled in power slightly faster, hitting 44% and 77% at the same respective intervals.

Among foldable rivals, Samsung's Galaxy Z Fold 8 and Z Fold 8 Ultra are capped at 45W charging. The Ultra model reached 49% in 15 minutes and 76% in 30 minutes, while the standard Fold 8 achieved 43% and 70%. The Motorola Razr Fold, leveraging robust 80W charging support, managed to recover 75% of its massive battery in just half an hour. The Google Pixel 11 Pro Fold lagged significantly behind, constrained by its slower 30W charging speed, recovering only 29% in 15 minutes and 56% in 30 minutes.

How We Test Phone Battery Life

Standardizing smartphone battery tests requires strict environmental controls. All devices undergo continuous 5G web browsing at a calibrated 150 nits of brightness. For foldables, tests are always run on the internal, primary folding display to simulate true power-heavy multitasking and media consumption. Running these tests simultaneously in a controlled setting ensures that external network and environmental variables remain identical across competitors.

Bottom Line

Ultimately, the iPhone Duo delivers a middling battery performance relative to single-screen flagships, but it punches well above its weight compared to standard foldable competitors. While it may not secure a top spot on the absolute best phone battery life leaderboard, it easily provides enough juice to get a typical user through a full day of mixed usage without requiring midday top-ups.

If maximum longevity is your primary criteria, sticking with a traditional bar phone like the iPhone 18 Pro Max remains the safer bet, as foldables inherently demand more power to illuminate their expansive displays. Nevertheless, for anyone transitioning into the foldable ecosystem, the iPhone Duo strikes a commendable balance between modern engineering and daily endurance.